91 stall issues (1 Viewer)

[semlin]

the 91 is having start/stalling issues. I am relaying these symptoms as I have not had a chance to check it myself yet. Will do when I get home. does this sound like the EFI relay issue? We have not done it yet.

1. it has always started first turn. yesterday it took about five tries to start it from cold, then ran fine.
2. today started fine but 10 mins later the revs started dying when turning through a corner with no gas. gave it gas and it recovered
3. then a few blocks later the revs started dying at a light, threw it in neutral and revs jumped to over 2000 rpm
4. then a few blocks later it stalled out at a light as soon as it stopped
5. took a bunch of times to restart again, started second time after it was given full gas.

 

[erics_bruisers]

fuel pressure regulator?

e

 

[Beowulf]

Sounds like fuel delivery. Pump, regulator, filter, or EFI relay.

-B-

 

[Seminole]

Fuel filter and couple of new vacuum hoses fixed mine. I still haven't done the EFI upgrade yet either, but no recuurence of those symptoms either.

 

[semlin]

Seminole, are you saying you had the same symptoms?

I still have no 3FE manual so can anyone advise where the fuel filter is located and what kind of fittings it uses? Will I need flared wrenches?

 

[Landpimp]

passager side frame rail(inside) kinda down around the starter. Normal wrenchs will work. Pop the fuel door, pull the EFI fuse when its running.......this will help releive the presure.........but its still a messy deal to do.

I wanna say 14mm but it might be 17mm. If I recall you will need a pair of the same size wrench as you need to hold the filter with one when you turn the fitting with the other.

oh and remove the mount for the filter from the frame, makes replacing the filer much easier.

Seminole, are you saying you had the same symptoms?

I still have no 3FE manual so can anyone advise where the fuel filter is located and what kind of fittings it uses? Will I need flared wrenches?

 

[semlin]

thanks Pimp, my wife just called to say there is a guy from out of town wants to look at the truck first thing tomorrow. isn't that always the way! I am going to try switching out the relay since it is the only part my local dealer stocks and sounds like a possibility anyway. the question is, where is it on the truck?

 

[PHAEDRUS]

Wich relay ??
I am at home so give me a call and I can pull out the bible.
Dave

 

[Landpimp]

EFI relay is under the hood in the fuse/relay block on the driver side fender.

seeing how it did it when cold I kinda doubt its the efi relay

Wich relay ??
I am at home so give me a call and I can pull out the bible.
Dave

 

[erics_bruisers]

it's the forward-most, right-most one -- circular -- it's labeled on the cover --

e

 

[semlin]

Dave, I would have called but no access to your home number at my home.

Anyway, to refine the problem somewhat after test driving

1. it is intermittant and does not seem to be a cold or hot issue. I got the problem twice last night in first 4 minutes from cold then drove 40 minutes without any issues. Earlier the problem did not surface until after 20 minutes of driving.

2. It is an rpm surge followed by a stall. When problem happens, as you slow down at a light the revs at idle go to about 1100 instead of normal 600 then it stalls when you give it gas to pull away. If you put it in neutral when this happens the revs jump up to just over 2000 rpm then it will stall when you go into gear.

As previously noted, it has apparently also refused to start from cold until 5 or 6 turns and sometimes when it stalls it won't restart for 5 or 6 turns. I haven't seen these symptoms.

3. the EFI relay contacts have a slight build up of black in the middle.

4. I can't find anything obvious from an inspection of engine bay. No vacuum leaks etc...

I am hoping it is a bad relay and I have a new relay ready next time it happens, but the behaviour seems more like something else since it does not miss or stall out immediately when the behaviour starts, but only when you give it gas. I would think something sticky in the throttle body but the stallout when you give it gas makes no sense. To put it in carb terms, It's like the choke is being randomly stuck in or someone is adjusting the mixture on the fly.

Anyway, on the bright side I am now a member of the 3FE board. Good guys over there. Haven't yelled at me yet about having no FSM.

 

[Landpimp]

check the conection on the air flow meter thingy, but DO NOT unscrew the screws that bolt it on. ALso check the thottle valve thingy(like the buterfly on a carb) might be gunked up. check the duct fromt he air cleaner to intake for cracks.

 

[semlin]

will do. thanks for the tip about the screws

 

[PHAEDRUS]

Simon,
go throught he 3fe archives and check on the diatribe on the fuel pressure regulator.
just for kicks that is probably not it my guess would be the maf or the butterfly as pimp stated. could also be something in the egr system but I doubt it.
check your pm for a phone number.
Dave

 

[semlin]

ok well after trying a replacement EFI relay and also cleaning the throttle body, the problem is sitll there. Then I noticed that the dash temp gauge was intermittently cutting out and the check engine light flashed a couple fo times so I checked and there is a stored code 22 meaning open or short in the water temp sensor signal. Could this create the symptoms?

Also, does the 3FE dash temp and EFI temp system share any common components? I can see three different sensor thingies on the water pump, one of which is vacuum operated, and two electric.

Not sure how much further I can go without giving in and buying an FSM even though it is for sale.

 

[landtank]

Sounds similar to Eric's problem with the dash cutting out. It was the battery cables. Nothing real obvious, just bad. Got something close to fitting the negative from AutoZone for like $10.00 which cured half the problem. The rest was fixed with the positive cable. If your power is cutting out I wouldn't pay any attention to what the ECU thinks is going on as it's not thinking with a clear head.

 

[dd113]

Re do the EFI main lead going from the harness to the batt. Pull, clean and reseat the ICS, TPS and AMM connections. Sounds electrical to me.