Fuel starved when cold?

[FreeUlster]

The last few winters my 91 would stumble and stall on accel or going up hill. No probs during warm days. I get no codes or check light. A few threads suggest fuel pump or relay. Would the cold effect these and where do i start?

 

[walterd140]

Could be water in the fuel. Colder days it will effect it more then warm ones. Try some dry gas at the next tank top off, then another bottle at the next & see if it helps.
Might also think about changing the fuel filther if you have not done so in a while

 

[FreeUlster]

I forgot to add that it wont start now. When i turn the key i hear the fuel pump hum for a sec then a click from under hood and the pump stops and starts again followed by the click. This happens over and over again. When i turn key to start it turns the engine but it seems like the battery gets weak then strong like the voltage is fluctuating.

 

[Four0Sport]

try switching out your fuel pump relay with the blower or abs relay, just to see it if cures the problem. if it does run out and buy a new relay, about $10. but deffinetly run some dry gas through the tank in the winter, never a bad idea.

 

[boggs1227]

like fourosport said .....fuel relay maybe going belly up ...what it sounds like to me at least .some people say you can clean the contact points on them but just better to replace it cause the metal strip in there will get weak over time or the electro-mechanical servo (the part of the relay that becomes a magnet to close the metal strip closeing the circut) ..can get weak over time .

any part that moves weither its a oil pump or a relay ...they all have parts that over time will wear out ...just replace it .

but then again i would check the fuel pressure to ...to see if the pump is good as well ..could not hurt.if it's a 91 and the fuel pump has never been replaced then maybe it's the pump slowlly dieing ( cold weather maybe letting you see the effects of age more so than when warm weather)

 

[FreeUlster]

UPDATE: I had a new unused blower relay from when I put in a new blower motor. I went out and bought new EEC and fuel pump relays. The EEC and blower relay had the same part number while the fuel pump relay has a different number, but the diagrams on the relays were all identical. I looked through my much worn Haynes manual and couldn't find which relay was which under the hood. I have green black and tan connectors but no labels to know which is which. Since the relay diagrams were identical on my new relays I just changed all three regardless of harness color. The truck took a moment to start and I thought I hadn't fixed any thing but once it started it ran great, no stumble or stall. BUT it is in the mid 40's while the morning I had trouble it was 23 out. However I usually would notice slight stumbling when it was under 50. I have run it up a few hills while the engine was still cold and got no stumble. I understand this is a way to test for a failing fuel pump. I will try again when it gets colder.

edit. I added dry gas as well and topped off the tank. I hope the pump doesn't fail when I have a full tank. That will suck.

 

[Four0Sport]

glad an easy fix did the trick

 

[FreeUlster]

Crap, 32 outside and sputtered uphill pretty bad and on flat road as well. Barely made it to work.

 

[walterd140]

Sounds like you may be facing a filther. Can't believe you have that much water in the line toi make it stall going flat.

 

[FreeUlster]

Still no joy and getting ready to take a BFH to the damn thing. :exp:

My truck died about 10 feet out of my driveway. It started right up Saturday morning, idled smooth. I put her in reverse and it backed up then died and wouldn't start. I could only turn the motor and it just backfired out through the air cleaner. When trying to start it the engine turns fast then slow then fast etc.. Later that day It stated and idled great and would rev smoothly over 2000 rpm. Put it in drive and it bucked and fought just to get it the 10 feet back into the driveway.

Today I get out there and notice there is no vacuum line going to the fuel pressure regulator and a port is capped on the "tree". The truck still will not start. I put a line in and no joy. I work 16 hour days and can't keep leaving my wife and baby home without a car. I'm getting pretty desperate.

If it is fuel pump related why did it idle and rev smoothly until put in drive?
Could it be tranny related, like a bad vacuum modulator?
It alway runs great when it is warm out but does this crap every winter now for 3 or 4 years. We had a third car then so It didn't matter but now we are down to 2..

 

[FreeUlster]

Bump

 

[MrShorty]

Probably the first thing I'd do if I suspected some sort of fuel problem would be to put a fuel pressure gauge on it. In your case, you may need to rig it up so you can watch the fuel pressure when it dies.

If it is fuel pump related why did it idle and rev smoothly until put in drive?

It doesn't take much fuel to idle. A weak pump or clogged filter or something could allow just enough fuel through to idle, but not enough under load.

 

[FreeUlster]

Wont even start now, don't think I'll get much of a reading. I just hate throwing parts at it until I get lucky.
Thank you though for the suggestion.
I've had this thing for 10 years and put 100,000 miles on it myself. Never got good gas mileage and lately averaging 8 mpg. Today I find there is no vacuum hose for the FPR, just a naked port on the FPR and no line anywhere to be found and a capped port on the tree closest to the fire wall. I'm guessing FPR but I really am guessing based on the missing vacuum line. Maybe the prior owner sold it because of this.

 

[Willard]

You could try the fuel filter, they are cheap, just can be a pain to replace unless you've done it before.

I know the fuel filter on mine clogged so badly I had 0 psi fuel pressure are the rail. It still ran fine though. Replaced it and got more power out of it though.

 

[FreeUlster]

I'll change the filter but don't understand why cold weather would effect it. I've had this problem for a couple winters now but runs great when it is warm out, except for the gas mileage being legendarily bad(8 mpg). Still leaning toward FPR. I would love to check fuel pressure but now it just cranks and occasionally back fires

 

[Willard]

I forgot to mention in my last post that when my filter was clogged it hesitated some until it warmed up. Then it drove fine.

 

[MrShorty]

Today I find there is no vacuum hose for the FPR, just a naked port on the FPR and no line anywhere to be found and a capped port on the tree closest to the fire wall. I'm guessing FPR but I really am guessing based on the missing vacuum line.

The engine will run just fine without that vacuum line, assuming everything is functioning correctly. Have you checked for gasoline dribbling out of the vacuum port on the FPR? If you haven't, ground the fuel pump test lead (KOEO) and see if anything is coming out there. That's a dead giveaway for a bad FPR. Beyond that, the only way to test the FPR is with a fuel pressure gauge.

 

[FreeUlster]

Well the weather warmed up today late in the afternoon it hit 50 degrees. I started the truck and disconnected the inertia switch and let it die. I have no garage (it's gonna rain the rest of the week and get cold again too) and since I only had an hour or so of light I installed a new FPR which wasn't much fun. I'd like to thank the guy that put it under the radiator hose and positioned the wire harness there too. But I did get it in and no leaks. Because it is warm I don't know if the problem is resolved. I didn't get to the filter but that is next when I get a break in the rain. I figured if I have to do the pump I was going to put a new FPR in anyway so I have a head start. The tuck does have nearly 200,000 on it and is mostly original from what I can tell.

 

[boggs1227]

i would also like the thank the same guy that put the exhaust pipe/ cat 10 nanometers from the transmission shift servos ...good one

 

[mikeinri]

Hi FreeUlster,

I would also have suggested the fuel filter for all the reasons mentioned. Odds are, it's probably due anyway.

I would also suggest that if that doesn't fix it, bring the truck in for a diagnostic. You'll end up saving money in the long run, rather than part-swapping until you get lucky. You can always just get a quote and do the work yourself.

Hope this helps.

Mike