95 Trans Sport won't start when hot

[Alerion]

Hello everyone.

I bought my -95 Trans Sport with 2.3L Quad4 engine a few months ago.
It has done some 313 000 kilometers. My current and baffling problem is that the car won't start when the engine is hot. A couple of minutes wait after turning off the engine is enough to bring about the problem.

The engine cranks, the oil pressure rises, but it won't start. IF it does, it idles erratically between 500-800 rpm and soon dies. Next morning it starst just fine.

Other, maybe related symptoms are:
- At times faulty fuel gauge. (stays at 3/4 tankfull regardless of the amount of fuel in the tank)
- High oil pressure for the first 5 minutes of driving.
- Sometimes misfiring when cranking with the gas pedal pressed down.
- Vacuum in the tank. A loud hiss when I open the cork. (By the way, I tried driving without the cork, but the problem persists.)

I suspect the fuel pump relay (btw where is it in this model?), the fuel filter or the fuel pump itself. Should I suspect ingition or PCM? I haven't read any error codes yet, I don't know where the plug is. The fuel filter has been replaced god-knows-when, if ever.

Ideas and hints are greatly appreciated. Knowledgeable repair shops in my area are few, and two of them have not found any reason for this problem.

Alerion

[96tsport]

Just a few comments...

Though I'm not familiar with the setup of your engine in your area (had one in another car though), depressing the gas pedal while cranking used to be done sometimes on engines with carburetors. Haven't seen that recommended (at all) on cars with fuel injection. Could be that it only starts that way with an unresolved hot start prob though..

Some engines (more so than others) do show elevated oil pressure on start that then lowers when the engine warms up, so probably normal. Unless maybe in a red zones (dunno what your gauge setup is). How high is it? Doubt it is related to a hot start prob.

Unless the fuel filter looks fairly new, I'd change it.

Basics need to be good, spark plugs, wires etc?..

My Haynes manual shows this for hot start probs:
1.air filter clogged
2.fuel not reaching injectors
3.Corroded BAT terminals,especially ground.

[Alerion]

Originally Posted by 96tsport

Just a few comments...

Though I'm not familiar with the setup of your engine in your area (had one in another car though), depressing the gas pedal while cranking used to be done sometimes on engines with carburetors. Haven't seen that recommended (at all) on cars with fuel injection. Could be that it only starts that way with an unresolved hot start prob though..

Some engines do show elevated oil pressure on start that then lowers when the engine warms up, so could be normal. Unless maybe in a red zone (dunno what your gauge setup is). How high is it? Doubt it is related to a hot start prob.

Unless the fuel filter looks fairly new, I'd change it.

Basics need to be good, spark plugs, wires etc?..

My Haynes manual shows this for hot start probs:
1.air filter clogged
2.fuel not reaching injectors
3.Corroded BAT terminals,especially ground.

Thank you for your reply.

From the user manual, I read that pressing the pedal down (and keeping it down for a while, while cranking) resolves the matter of plugs being flooded. It did not help though. I too think that the oil pressure issue is not related to the matter at hand, but at least it provides the fact that the secondary mechanism of giving the fuel relay a go, is allright. The oil pump is working.

The air filter was replaced 1000km ago. Battery terminals are ok. So my strongest suspicion is that the fuel is not reaching injectors.

It seems that this is a bit of detective work and I have to start eliminating possible causes one by one, starting from the cheapest (since i'm going to sell this bastard instantly when this problem is solved). I will start with the filter and pump relay.

Can anyone tell me where the fuel relay in this model is located?

Alerion

[96tsport]

Finding the codes will help greatly. Just had that done for the first time recently (had some last minute probs..) & details given included which spark plug was misfiring. After changing the plug & wire, engine hummed but if it stayed the same, would have pointed to a F/I problem in that cylinder.

Having codes allows dealing directly with know probs first, rather than chasing a problem & often changing good parts.

[cartherapist]

Get a fuel pump pressure test. If it is even a small amount below spec you'll have problems; if you change the pump you have to change the relay and examine the wireing terminal at the relay; they melt. Your fuel gauge issue makes me suspisious of the pump, they are part of the same module.

[Alerion]

Originally Posted by cartherapist

Get a fuel pump pressure test. If it is even a small amount below spec you'll have problems; if you change the pump you have to change the relay and examine the wireing terminal at the relay; they melt. Your fuel gauge issue makes me suspisious of the pump, they are part of the same module.

Thank you all again. I have had this car seen to in two different repair shops and neither could find any problems (which is because after a night's rest, the car starts normally). One shop also said that they could get no error codes. Are these errors stored indefinately or deleted if engine runs normally?

I also read from other forums that if the fuel tank is under a strong enough vacuum, it folds and may break some equipment inside. Can this be true?

Alerion

[LMP]

FUel tank is under a slight vacuum...normally.
A common failure on almost all engines that refuse to start once hot is crank position sensor gone haywire. THen engine would also usually stop when waiting at red light ..once warmed up. Consider this possibility.

[96tsport]

Ran across this in the caravan forum. At first, diagnoses was a possible fuel pressure problem but it didn't go away with another used pump. At this point, a fuel rail has been replaced & so far ok. http://www.automotiveforums.com/vbulletin/showpost.php?p=5785124&postcount=8

Re: 89 3.0 engine hard starting when warm

I'll bet that the problem is a bad fuel pressure regulator. It's leaking past the diaphram and raw fuel is being sucked into the intake, especially when there's a high vacuum (like when coasting/engine-braking to a stop). Rough too-rich-like idle. Hard to start . . . take several seconds of cranking and some push on the pedal to get it to fire, whereas before one turn of the starter and no pedal produced an instant start.

It would also explain the leak-down and the fact that the computer is throwing no codes.

Turn the engine off, then disconnect the vacuum line to the pressure regulator and turn the key on. The fuel pump should come on momentarily until it builds up pressure. At the same time I'll bet there will be a geyser of fuel squirt out of the vacuum connection on the pressure regulator.

A new fuel pressure regulator is about $60, and you have to remove the fuel rail to install it.

One thing you could try that might give some insight is prepare yourself for a hot start situation & after attempting a start, pull a spark plug or 2 (or all if easy).

If it's soaked in fuel, that's one thing, If it's bone dry, that's another.