A Possible and Minor Vapor-Lock Cause with My Old Trooper

BonzaiDuck · Apr 6, 2024

Yes, you have known for about five or six years that I am obsessed with this old, orphaned '95 SUV.

And people who are OCD about their vehicles may take some little thing, expand it in their imagination and worry or fret about it without end!

Couple weeks ago, I took her in to my Solid Gold repair shop, having laid the groundwork for the visit over more than a year. First, I wanted to replace the gas-tank sending unit that informs the needle gauge and an idiot light ("tank-empty") on my instrument-panel/dashboard. I found the original part brand-new in ISUZU carton through the US ISUZU parts depot, who found it in a warehouse in Japan. For $135, I had to wait three months, but I got it. I planned with the service advisor, who provided an estimate, to do it this spring.

And before I took it in for the work, I thought I noticed a "hard-starting" situation to which I'd not paid attention before. Since the sensor replacement meant removing the gas-tank, and a new fuel-pump ($150) required the same thing, we all decided the Trooper deserved it after 200,000 miles.

The car was returned to me. The idiot light was behaving properly. And the vehicle ran like new. [It just occurred to me I posted another thread about this, so I apologize]. BUT -- ANYWAY!

The owner and service advisor both affirmed that the Trooper "just starts right up -- no problem". The car had been sitting for a few hours when I went to pick it up, and they seemed absolutely spot-on -- "It starts right up!" Now, later on, I discovered that this was always the case when the engine was cold. Further, if I returned home, turned the car off in the garage, waited FIVE MINUTES or so and then turned the key again -- it started right up! Great! Now I've discovered that if you let the car sit for 20 minutes to an hour or so, the starter would crank for about 10 seconds -- maybe more -- if you tried to start it.

Pumping the gas or hitting the accelerator once or twice before turning the key seemed to reduce that time.

It seems to be a vapor-lock situation. Just after the car has been driven, some part of the fuel line is still cool from the car's movement. After it sits, there is no draft from the fan, no air coming through the radiator -- and it heats up before it cools off.

This may have been a condition for the entire time I've owned the car -- I can't be sure. But what can be done about it? Should I try and insulate gas hoses or lines running to the engine? I discovered today that putting a fan on the engine after putting the car in the garage eliminates this starting delay if I come back and turn the key in less than an hour.

RLGL · Apr 7, 2024

I cold, it's not vapor lock. Is this beast fuel-injected? If so do a key on fuel pressure test.

BonzaiDuck · Apr 7, 2024

RLGL said:
I cold, it's not vapor lock. Is this beast fuel-injected? If so do a key on fuel pressure test.

Yes -- fuel injection. What do you mean by "I cold, it's not vapor lock . . . "?

I suppose that I'm keen on this matter of the starter turning over too long when the engine is still hot after sitting more than 10 minutes -- I just replaced the starter motor last year, so I don't want to increase wear and tear on it.

At the time my shop replaced the tank sensor and fuel-pump, they did a fuel pressure test. Are you saying to do the pressure test with the key on?

I'll keep an eye on this thread for now. I've got the driving fever. I need to buy some half-and-half for the sunday coffee. So I'm going to run it out today. Maybe visit the truck-farm canopy for some vegetables -- anything! Drop by Carl's Jr for a chicken sandwich. The Trooper's Manitou beckons like a dog who wants to go for a walk . . .

Torn Mind · Apr 7, 2024

Do you mean the thing does not start easily when hot?

Your fuel injector seals might have failed and liquid gas is being dumped into a cylinder....

Hans Gruber · Apr 7, 2024

It's probably time to retire that Trooper.

Toastedlightly · Apr 7, 2024

I had a similar issue on an 89 Trooper (it had the cylinder though). The symptoms are almost the exact same. The diaphragm in my fuel pressure regulator had ruptured allowing fuel to pour into the vacuum system and into the engine. This can easily be tested if you take the vacuum hose off the fuel pressure regulator. If fuel comes out of the regulator that could be it.

The second one I could see if is if the engine temp sensor is bad. It may be giving the engine the signal it is cold and thus it starts well cold but refuses to restart. On my older Fords the ECU used a separate probe from the one used for the gauge (unsure about the trooper).

Torn Mind · Apr 7, 2024

Toastedlightly said:
I had a similar issue on an 89 Trooper (it had the cylinder though). The symptoms are almost the exact same. The diaphragm in my fuel pressure regulator had ruptured allowing fuel to pour into the vacuum system and into the engine. This can easily be tested if you take the vacuum hose off the fuel pressure regulator. If fuel comes out of the regulator that could be it.

The second one I could see if is if the engine temp sensor is bad. It may be giving the engine the signal it is cold and thus it starts well cold but refuses to restart. On my older Fords the ECU used a separate probe from the one used for the gauge (unsure about the trooper).

Some good advice when testing fuel pressure regulator in this vid.

pcgeek11 · Apr 8, 2024

I highly doubt you have a vapor lock...

https://www.motortrend.com/how-to/engine-vapor-lock/

A low pump pressure could cause it, but you stated the fuel pressure checked by the mechanic and was fine.

BonzaiDuck · Apr 12, 2024

TornMind, PCGeek and ToastedLightly have some useful ideas which I will explore.

Hans! That's what my dentist told me when I mentioned that my rental property was being listed for sale! "You've likely got 14 years left to live. Spend the money! Buy a new car!"

I bought the SUV in 2002 -- six or seven years old. I started an Excel spreadsheet immediately -- with DATE, MILEAGE, DESCRIPTION and EXPENSE columns. A person might look at the history and ask "why didn't you get rid of it when . . . ?" But it shows that I've spent $100/month (average) since I bought it, including the purchase price in the items averaged. Ideally, it cost less if I subtract the repairs made for my own negligence or a repair shop's choice of defective parts.

The engine is simply going to "keep on going" until it somehow dies. It doesn't pollute; it doesn't leak; it doesn't burn oil. The transmission has relatively fresh fluid in it, and shows no signs of needing service since I replaced the original in 2004.

So -- today is Friday, heading toward COB/close-of-business. I"m going to run it by the repair shop next week with the list of ideas for possible causes. They'll find the trouble, and they'll fix it.

It seems that the problem -- accepting the ideas of a cause -- is pretty minor. It isn't that I cannot start the car when it is warm. I need to pump the gas once and turn the key, at which time it may turn over with some noticeable delay.

The problem with buying a new car -- excluding all of my financial strategies to spite late-life circumstances -- is the hassle of looking for a vehicle, selecting a vehicle, negotiating, and the learning-curve on new technology. That is, these hassles, weighed against repair episodes for an old car. But mainly, if I only drive 4,000 miles per year, the Trooper otherwise runs great to original specs, and it doesn't cost me much --- I can't see that sinking $50,000 into a new car which will only be driven 4,000 miles/annum -- I can't see that it is worth it. It doesn't make sense.

Instead, if I can get 5% return on $200,000 for three years, buying a new car may seem painless, but it doesn't make much more sense. They only reason it would make immediate and emergent sense arises when the Trooper has truly, entirely, completely died. Or it gets totaled in an accident -- which seems more likely even as accidents should be unlikely.

BonzaiDuck · Apr 12, 2024

Toastedlightly said:
I had a similar issue on an 89 Trooper (it had the cylinder though). The symptoms are almost the exact same. The diaphragm in my fuel pressure regulator had ruptured allowing fuel to pour into the vacuum system and into the engine. This can easily be tested if you take the vacuum hose off the fuel pressure regulator. If fuel comes out of the regulator that could be it.

The second one I could see if is if the engine temp sensor is bad. It may be giving the engine the signal it is cold and thus it starts well cold but refuses to restart. On my older Fords the ECU used a separate probe from the one used for the gauge (unsure about the trooper).

Before either testing it myself or having my shop do it, I think there's a good chance above all that the fuel pressure regulator -- "the fuel injection pressure regulator" or "fuel pressure control valve" -- is the culprit. That's a $50 part. But I think this was an item where ease-of-repair drives the bottom-line: I think one must remove the entire "common chamber" or intake manifold to allow removal of this part. I believe I asked someone to do it two or three years ago, and they discovered the removal problem.

That I decided to try and replace it was not based on testing, but it was an item that was cheap and I just had it in mind to make the replacement. The shop manual only speaks to diagnostics -- it shows the position and shape of the regulator/valve, but there are no enumerated steps for its removal.

Thanks for your input, based as it was in firsthand experience. And of course, since they can test the valve, if it's the temperature sensor it might not be so troublesome.

BonzaiDuck · Jun 18, 2024

MANY THANKS TO TOASTEDLIGHTLY AND HIS OLD TROOPER!!!

I replaced the MAP sensor on my own, and city gas mileage improved about 1 to 2 MPG. But I wanted my shop to address the hard starting when the engine was still warm.

The shop has confirmed that the fuel pressure regulator is defective. I really have hopes that city MPG will return to the factory EPA spec.

pcgeek11 · Jun 19, 2024

BonzaiDuck said:
MANY THANKS TO TOASTEDLIGHTLY AND HIS OLD TROOPER!!!

I replaced the MAP sensor on my own, and city gas mileage improved about 1 to 2 MPG. But I wanted my shop to address the hard starting when the engine was still warm.

The shop has confirmed that the fuel pressure regulator is defective. I really have hopes that city MPG will return to the factory EPA spec.

Just as I thought...

BonzaiDuck · Jun 19, 2024

pcgeek11 said:
Just as I thought...

We're also going to replace the injector O-rings, since the intake manifold/common-chamber has to come off to replace the fuel pressure regulator.

We collectively think that the engine, with 201,400 miles, is in great shape, and could last beyond my expected lifespan. So all the other sensor replacements and these labor-intensive-expensive operations are probably a good idea.

I embrace the distorted judgment I probably have about this old beast as a matter of personal attachment. I'm beyond the cold objectivity about "sunk cost" and other things. But in this case, there's a high probability that I'll retrieve the benefits of that sunk cost with the measures we're taking now.

I might even have two body panels of the Trooper repainted, but there's no risk of rust for the duration if I don't do it.

Everything I asked to be done is going to cost me close to 2 grand. But the expectation is for this vehicle to be totally roadworthy and reliable for a long time to come. I'm going to spend the money. I won't even get the car back until Monday, but I'm already happier than a pig in s***!

Muadib · Jun 20, 2024

You would be lucky to get $850 for it, and that's for a perfect vehicle. A dealer probably would give you $350. Why would you spend 2k on it?

mindless1 · Jun 20, 2024

Muadib said:
You would be lucky to get $850 for it, and that's for a perfect vehicle. A dealer probably would give you $350. Why would you spend 2k on it?

Okay but what can you get for $2K that won't need a list of things done to it now or soon enough anyway?

It is a tough call, committing to longer term vehicle maintenance if you don't DIY as much as possible, but you can easily spend $2K on repairs for any vehicle these days if you don't DIY, and if you get something a lot newer, can watch it drop in value by $1K/year or more in depreciation even if you hardly drive it.

Everyone has their own budget and # of vehicles to fall back on, but i like the $1K/year concept. If you reasonably expect it to last another year for each $1K spent, it can be cost effective to keep it going.

There's the insurance cost too. Something a lot more valuable, I'd want full comp insur. on. but a $1K vehicle not so much. The savings in depreciation and insurance alone can more than make up for repair and supplies costs (including tires), and even buy you a large array of tools if you can then DIY.

I'd consider it worth $2K to keep going if the engine is in good shape as suggested, and no apparent transmission issues, and frame not rusting through. However if not DIY then you have to trust your mechanic, can blow $2K and not fix problems and keep spending till something becomes a money pit.

The real question is, do you want to keep driving it. Some older vehicles are in better shape than others, and some drivers have their own opinions about what is important to merely get from point A to B.

pcgeek11 · Jun 20, 2024

The beast you know is always better than a gamble on the beast you don't know....

I tend to keep vehicles longer than normal.

Good for you OP!

Muadib · Jun 21, 2024

I hear you, and if he was younger, I would agree with you. However he’s in the twilight of his life, and he should be enjoying the time he has left. Besides that today’s vehicles have improved greatly since the 90’s. The safety tech alone would be quite helpful to him. I could go on, but I think my point is made.

Torn Mind · Jun 21, 2024

He operates under the visceral will to treat the belonging as an object of care. That is why his actions may not appear reasonable in an economic framework.

pcgeek11 · Jun 21, 2024

In the end it is his life and his choice.

Best of luck @BonzaiDuck !!!

BonzaiDuck · Jun 22, 2024

Muadib said:
You would be lucky to get $850 for it, and that's for a perfect vehicle. A dealer probably would give you $350. Why would you spend 2k on it?

USE-VALUE. The vehicle has USE-VALUE to ME. With the highway gas-mileage I can expect, it will take me to and from a destination hundreds of miles from here for mostly the price of gasoline, or about 37% of the expense to rent a car for 10 days. I get continued USE out of the vehicle without incurring a car payment or full insurance coverage.

I understand the logic people follow about "trade-in" value, but a person is just replacing one cost/expense regime with a different one. In my mind -- with calculations based on a $10,000 resale value after six years have expired, I've saved about $60,000 keeping this single vehicle running as opposed to trading in a six-year-old vehicle every six years for 18 to 22 years.

I could purchase "new technology". My dentist argues that if I buy a new car, it will help attract "chicks". I could get better gas mileage with a new car -- and the dollar-value of that factor is easy to calculate or estimate. I could have prestige among people I may never meet socially, just for passing them on the highway.

I'd rather have the $60,000 -- in something like a defiance of a culture which has evolved in modern-day America with the automobile.

Thanks for the input of mindless1, pcgeek11 and the rest of you.

HERE'S A BIG UPDATE!!! VERY BEEG ONE!

I said somewhere else that the forums need a "personal financial management" forum. Set that aside: I stopped using my credit cards as a revolving loan program more than 25 years ago. I avoid paying interest on ANYTHING. I own my real-estate outright; I own my cars outright; I will BUY my cars outright.

That being said, I have about five or six credit cards which each have certain limited purposes. One card I use exclusively for medical expenses -- like dental work. Another one I use for "subscriptions" and particularly my streaming subscriptions. I use yet another one mostly for gasoline, car repairs, and groceries. In my forward budget planning, all of these cards have a monthly budget, but in this case -- the car repairs -- I've vastly exceeded routine charges of the monthly budget.

OF COURSE I was going to pay off the card in July for the expenses incurred in June, including the approximately $2,000 or so spent on this "project". For that, I was going to draw from my savings account -- something I don't like to do very often.

I never paid much attention to "credit card cash back rewards". I always thought it was some gimmick. But two years ago, I discovered my Amazon card had enough "rewards" to pay for a new Sony HT receiver. It was a surprise to me.

This credit card I use for automobile repairs has been in my wallet since the mid-1980s -- a long-standing VISA account. I went online to refresh myself and make a review of it.

I had racked up 143,000 "Cash Back" points on this sucker! This translates into $1,430 credit against charges on the card! Was it "free money"? My friend argues -- "No -- you 'earned' it." But to my PERCEPTION, it was assets I never recognized having.

So NOW, I HAVE MORE "RESPECT" FOR DINGY COMMERCIALS THAT SAY STUFF LIKE THIS: "IT'S NOT A GAME!! IT'S CASH BACKIN'!!"

THE TROOPER RIDES AGAIN!! Hi-Ho-o-o-o!!!! I WILL follow the advice of a friend since high-school: next year I will buy a new or maybe a 3-year-old pre-owned vehicle. She argues that we'll be 80 years old in less than 4 years, and I might not be able to drive soon thereafter. So in the sunset of my life, I "deserve a new ride".

But! The Trooper I will keep as a backup ride, and until I feel comfortable -- even "proud" -- of the new vehicle, it's likely to be selected for daily use just as much as the new one.

Muadib · Jun 23, 2024

pcgeek11 said:
In the end it is his life and his choice.

Best of luck @BonzaiDuck !!!

True, but life is so very short, make the best of it! I'll go back to biting my tongue now.

mindless1 · Jun 23, 2024

So much drama about merely repairing a vehicle. Is it a mental block about vehicles over a certain age? I don't really buy the argument about features if it costs a premium to get them, and safety, well if you consider that the vehicle has managed to stay on the road this long, with same owner, it's not (yet) proving to be unsafe at all. Theory about crash protection or whatever, has to be weighed against the minor odds of who hits what and where and... it's not that clear cut.

Besides, some modern supposed safety features can be dangerous. Have you ever heard of vehicles with lane assist, driving behind another vehicle, and something falls off the vehicle ahead, then the driver would swerve out of the way but the lane assist puts the vehicle right back into the path of the object? Happens all the time. It also gets confused by road construction, and many scenarios where it isn't just a smooth empty road with lines to follow. One thing it is for certain though, is added expense later when it fails.

Many people prefer older full frame SUVs, more durable, easier and cheaper to repair, and if kept in good working order and minimal rust, are arguably appreciating in value at this point. The one thing it has against it on that front is being an Isuzu... so yeah it's not a Bronco or anything but we're talking a very small amount of money here, in the grand scheme of vehicle ownership, to merely fix problems like anyone would do to keep their vehicle running. Again this is unless it is eaten up by rust.

Life is too short to have a nice, classic SUV that's actually capable of going off-road without spending $75K? Depends on what you need out of it. That's exactly what many people want, to NOT take a $75K vehicle off road much. In that regard, you never know, if it comes time to sell, might set a high price and see if it gets any interest, if he doesn't need that functionality.

If it is real low rust and cleaned up nice, it would not surprise me if he can get $2500 for it in this not so far past covid car market. With it running properly, of course. 5 years from now, maybe not, hard to say if it will retain value or drop like everyone expects the rest of the used car market to do as it readjusts to the fact that dealers are losing money by being unable to sell their arguably overpriced new inventory.

Just buying a replacement vehicle right now, if it's not very old, you could lose more in market value than the cost to repair the Isuzu, possibly double that if you count depreciation. Literally driving it for another 18 months might pay for itself.

Life is too short, yeah, it is. You won't go to your grave wishing you drove a newer vehicle. It just isn't on the list of regrets for almost anyone and it is insane to pretend otherwise. Wow, no.

Muadib · Monday at 8:30 AM

mindless1 said:
Life is too short, yeah, it is. You won't go to your grave wishing you drove a newer vehicle. It just isn't on the list of regrets for almost anyone and it is insane to pretend otherwise. Wow, no.

How could you possibly know that? Are you psychic?

BonzaiDuck · Monday at 12:05 PM

Muadib said:
How could you possibly know that? Are you psychic?

I'm on "pins and needles" today. Soon -- before COB today -- they'll likely call me to inform that the Trooper is "ready". I was told they were test-driving it Friday. The only loose end: the engine around the oil pan "sweats" oil, so over a week, a very thin film builds up on the drop pan. Initially, I wanted them to locate the leak -- and, if not due to the rear mainseal -- to fix it. A very minor leak at the mainseal might only justify the response that "all old vehicles leak oil" --in view of the expense to repair it. But at this time, we're only going to find the leak with a dye visible with "special glasses", and then decide one way or the other.

If this proves to improve gas mileage by nearly 40%, I won't be in a hurry to put myself in the seat of a 202X RAV4 hybrid. I'm going to continue "looking into it."

I also thought it would be great to have a 4Runner hybrid, but there ain't no such animal. The other option is a Hybrid Highlander. This -- if I want to replicate features of the Trooper in its size and handling. But I should also look at PRIUS models.

Conventional wisdom, as some have used it in this thread, suggests that you must somehow avoid spending more than the BlueBook or Edmunds value of the used car. Or, that you must keep a car only until it still has "trade-in" value against a car that is maybe six years newer.

But barring engine replacement with transmission replacement and a bunch of other concurrent things, most repairs and maintenance are still a reasonable price to pay for just keeping a vehicle on the road.

mindless1 · Monday at 2:13 PM

Muadib said:
How could you possibly know that?

I know that because it is a tool, a means to get from point A to B. It's what you do at these locations that makes your life better. If you're off in la-la land mesmerized by your vehicle while getting there, you probably shouldn't be driving. This is within the condition that an older vehicle still works properly, is not in a state of decay where it is less safe to drive than it should be.

I happen to have both a newer SUV, and an older one. The primary difference to me is that I don't take the newer one out in nasty winter weather, and don't take the older on long road trips or outside cell service areas because there is a higher chance of break down and since I DIY all work to it, there is a substantial difference in cost to have towed a short distance home to repair myself vs having to pay some shop because longer distance towing gets expensive.

The cell service factor isn't one I even think about much because I live near a major metropolitan area where you have to go out of your way to not have service. If you happen to live where service is bad and may not see fellow motorists for a long time, that would be a consideration. Older SUV, hasn't left me stranded once after many years of ownership, though there was a time when the alternator failed and I got it home on the reserve battery capacity because I only had 3 mi to go. DIY new alternator was something like $120. I have AAA so if it had ran out of juice and had to be towed, probably free tow.

A Possible and Minor Vapor-Lock Cause with My Old Trooper

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