FyreLance

My 91 Formula is really beginning to irritate me. I've spent more time working on it than I have driving it since I got it a few weeks ago.

Here's the deal. I'll be driving around no problem for some time, then all of a sudden the engine will cut out and I will stop accelerating. It's like I ran out of gas. It will start "missing" (if that's the right term) like this, cutting in and out, with a minute or so in between, then a few seconds in between, and eventually the car will stall out and die. (I've gotten stuck on the highway more than once.) Then the car will not start for quite some time. The longer you let it sit, the better chance you have of firing it up and getting it home. I figured a dying fuel pump made sense, so (after a LONG down time since I was learning along the way) I replaced it. Fired it up and drove it around town and even to work and back which is a 15 minute drive, no biggie, and then the problem started again. Later that night, driving around town, it started choking and just died in the middle of the road. Had to PUSH it this time to get it out. Waited 15 min. or so, started it up and drove it home around the corner. Okay. The next day (which was today) I replaced the fuel filter, thinking maybe it was clogged (and I'm sure it could use replacing, looks like it's been there forever) and put it on, and I just drove it around the block a few times and it was cutting in and out. !!! How frustrating! It does seem to accelerate the process if I put the gas down (just now it happened instantly every time I went WOT, the engine would just stop pushing the car, then I let off the gas a little bit and it was okay to get it home. I am in dire need of transportation to school and work every day and I am REALLY getting tired of getting stuck on the way and calling for rides and missing work. PLEASE somebody help me!

[EDIT: Changed "the right turn" to "the right term". Oops. ]

Mark A Shields

Might be a long shot, but check your cat to make sure it's not clogged. After the car warms up see if it glows, best at nite.

FyreLance

Don't have one. ;-)

SkyWarrior

I havethe same problem, but only when it's like85 degrees or warmer outside. I changed my cat and it didn't work, but since you dont have one, no matter. Doesyour car have egr? If the egr valve is malfunctioning it causes combustion chamber temps to rise, and in my opinion makes the fuel boil. Of course this is only a guess. I just turn on my fan when the temp gets too close to 220. I hope this helps.

FyreLance

Hmm..dunno..how can I check this?

Temps don't seem to rise though...

SkyWarrior

You could see if your car is throwing the egr code.

FyreLance

I don't have a check engine light coming on. (That, or, it won't run long enough for it to occur.. :P )

SkyWarrior

I don't know what to tell you. Does this problem happen in all weather?

FyreLance

It has happened in rain and shine, at all times of day.

SkyWarrior

you could check your egr to see if it moves freely. stick your fingers underneath and push up on the diaphram thats inside the big round part. If it's too hard to push it's worn out. It could cost up to 50 bucks for a new one.

RedFirebird

Your car has to get pretty damn hot to make fuel boil and cause these kind of problems, by which time you'd have a ton more, unless it was a fuel pressure problem but it doesn't sound like it is. A bad egr could cause similar problems but the egr's only real chance of "choking" the motor is at idle. This might not be the exact problem but a basic tuneup would be a good start (ignition module............).

Bluebird

Check your fuel pump relay.. not the fuel pump.. the relay!

it is located on the drivers side somewhere by the brake
booster.
This might be the prolem.

Mark

FyreLance

Well my new fuel pump is pretty loud (especially since I haven't fixed the hole I cut to change it, heh) and I can hear it working, and when we had the fuel filter off I turned the key and it launched gas pretty good... but I suppose the relay could cause it to cut in and out?

How to I check the relay?

TomP

Is the car in good running shape otherwise? IAC motor/passageway clean? TB clean? Timing correct? Plugs gapped correctly & not fouled/wires at proper resistance/cap&rotor clean and not damaged? ( http://www.geocities.com/tomp_3rdgen/burnt-cap.html )

Oh, duh. Change the ignition module. You just described the classic ignition module failure! Drives okay when cold, when hot, the motor starts to stutter, and then the car dies. The car is driveable as soon as the module cools down- and then it happens all over again.

This requires a distributor rebuild, which isn't bad at all. It's described in any Haynes manual. Make sure you also replace the pick-up coil while you're in there! (It's cheap enough.) The hardest part of the rebuild? Getting the distributor out of the car, and then, getting it back in without throwing the timing off. (Go to the V6 forum, click on Search, and search the V6 forum for "distributor rebuild"- I've typed a ton of info there that would be useful for you.)

Next time you get stranded, if you have a bottle of water and a rag, you can do what I did when I was left on the side of the road. With the engine off (well, it's stalled by now), soak the rag with the water. Then, hold the rag to the bottom of the distributor- it'll be HOT! This allows for some heat conduction between the hot distributor/module and cold rag, and will help cool the module faster. When the rag gets too hot to hold, take it off, put more cool water on it, and put the rag back against the bottom of the distributor's base plate. You might get on the road a bit faster. But change this module quick!! It should take a couple hours if you work slow.

You can't buy a performance pick-up coil; by nature, the pick-up coil can't be improved. (It senses magnetic pulses.) Stock pick-up coils are about $15. A stock module is $60, Holley's performance module, HLY-891-103 from Summitracing.com is also $60. Here's the link to the module: http://www.holley.com/HiOctn/ProdLin...A/891-103.html You have a remote coil HEI, right? If not, call Summit and ask for a correct part #. Make sure you use the heat sink grease between the module bottom and the distributor base!! I bought an extra tube of the stuff from Radio Shack- I prefer to use the white grease, and Radio Shack sells a small tube of it for $5. I've seen mechanics use regular clear silicone grease; it might work, but as a former electronics junkie, I prefer the white stuff.

88TPI406GTA

Actually, you are all wrong so far....J/K had to start my answer out right

The big thing here is ignition or some electrical component. It sure sounds like either the control module...#1.... or coil...#2....but either way, something is heating up and failing. I personally would be thinking the module is to blame. Why? The instant cutting out, then letting it sit and being able to start the car again...Have it tested about 6 or 7 times in a row and I am sure you will see the failure.

I know cause I have had different types of GM/Ford modules fail and the symptoms are similar.

The instant "miss" should be your first clue to check ignition first...

Good luck.

TomP

I dug up a link for you:

https://www.thirdgen.org/techbb2/sho...ibutor+rebuild

Here's another:

https://www.thirdgen.org/techbb2/sho...ibutor+rebuild

And one more, with Kevin S changing the fuel pump, and still winding up with no spark:

https://www.thirdgen.org/techbb2/sho...ibutor+rebuild

Riley's35089rs+

Bad pickup coil will do the same thing...the control modual should only cost around $20.00. another 20 for the pickup coil..same thing mine was doing before I rebuilt the distributor

nebulous

Since I'm always fixing my 91 TA, I have a fiero GT to get around in. I had almost the exact same problem for two different reasons. One, the EGR tube was cracked, which with your TPI setup is unlikely since its built into the runner, and the ICM fried.

FyreLance

Thank you all, you have been most helpful. And thank you for taking the time to dig up those links, Tom, will check out.

Anybody else have any suggestions? Keep them coming if there are, I've tried a few more things and nothing helps, so the more suggestions the more I have to work with.

I'll research the ignition stuff from the hyperlinks, I'm not an experienced mechanic (this bird is becoming my learning tool, heh) so hopefully it isn't too hard...

mckenzie

sound's like an ign. module to me. heck try the "tap" test on the ecm. with engine running, lightly tap the ecm with the handle of a screwdriver. if it acts up when tapping ecm, the ecm may be bad. best of luck, tom

FyreLance

Fuel Pump: $80

Fuel Filter: $8

Ignition Control Module: ~$40

Fuel Injector Cleaner fluids: ~$10-20

STILL NOT WORKING: Priceless.

mckenzie

the key here, is to find out if your losing spark or fuel pressure. you can pick up a spark tester for appx $10, and a fuel pressure tester for appx $30. when veh dies, pull off a plug wire and check for spark. if none, probably fuel issue. buy a spark tester first and when it dies make sure you have spark. then let us know what the results were. we need to narrow it down to a spark or fuel issue. best of luck, tom

SkyWarrior

I just changed my ign. module today. I did it with the distibutor still in. It was a piece of cake, just dont forget to use the white goo that comes with it!

FyreLance

I already changed it, it didn't help.

It would appear that I am not getting spark, but I don't have a tester, I just held it close to the block. But I dunno. I'm getting really frustrated, my car has sat more than I have driven it and I NEED to drive.

FyreLance

Oh, and the worst part: my temp tags expired while it was sitting there on the road, and I didn't have a chance to have it e-checked (even though I know it's gonna fail), now they won't give me new tags which means that I am going to have to TOW it to e-check, even if it's working perfectly fine.

TomP

Here's a chart I posted on the V6 forum, it should be somewhat accurate for your car. (We both have remote coil HEI's, and I was typing the chart from Helm's '86 V8 TPI section. So any differences would be related to 86 vs 91.) It helps you check out voltages... https://www.thirdgen.org/techbb2/sho...hreadid=103866

Hey, wait, you're not getting ANY spark now?

FyreLance

No, after its' heated up and the problem starts.

I think...

I dunno, I think I'm gonna give up and take it in to a shop tomorrow.

chrisandkristin

i would try your maf (mass air flow sensor) same thing happened to me i would be driving down the road and then all of sudden it would die after sittinf for like 45 sec it would start up and run like normal hope that helps.....also check you maf relays

bills82z28

control module

TomP

Okay, then, definatly the module. If you had no spark while the car was sitting, it could've been other things, like a bad power wire to the coil.

94-6spd

Have you tried a new coil? Also, if you just had your ign. module checked at the parts store it may not be very accurate because it has had time to cool down when you get it in there.

spartyon

the fuel pump seems to be going. or at least sounds that way to me. that did the exact same thing to me about 4 months ago. same symptoms and everything and my fuel pump **** the *****. so i would suggest check the fuel lines in and out then filter and buy yourself a new pump. thats what i did and no more problems. only if u disregard the fact that i had piston slap in 3 cylinders and some serious blow by but otherwise it ran like a charm.

1986redbird

I had a similar problem with a 86 GMC pickup--305 4bbl. it would run fine then out of the blue it would die, if I let it sit for a while it would restart just fine, come to find out I had a crack in the distributer cap that was letting enough high voltage get into the ESC side of the system and overload it and shut it down, after letting it cool down it would be fine unitl it heated up again.

I ended up replacing the ESC and the cap to fis the problem.

FyreLance

:: sigh :: You people need to read all my messages.

Since I have said that I replaced the fuel pump, fuel filter, and ignition control module, all of those things have been suggested again....

None of those have worked yet....

FyreLance

Would the crack in the distributor be visible or could it be such a fine line that the only way to know is replacing it?

spartyon

SORRY DUDE. JUST TRYIN TO HELP. JUST SHARIN SOME OF MY EXPERIENCES TO HELP U ALONG AND I DIDNT JUST SAY THE FREAKIN FUEL PUMP. GO READ THAT CRAP AGAIN BEFORE U GET PISSY.

spartyon

did u check the pickup screen for the gas tank and all the fuel line for rust in them. my buddies 89 honda accord had the same problem andhe had rust in the tank which got up causin him to die on the road and then if he waited like 5 hours it would be fine. we just replaced everything from the tank forward up to the carb or whatever crap u have

FyreLance

Hey now, I wasn't getting pissy... I inserted a which indicates sarcasm, I wasn't trying to start stuff. Sheesh.

I really do appreciate the help, but I'm just saying I already fixed all those things and it hasn't helped yet.

Bralgar

you check for a shorted O2 sensor, it reaches temp and shorts?

FyreLance

How do I check that? With a DMM? (Don't have one yet...) Where's it located?

TomP

Want an $80 DMM for $15? Go to http://www.sunpro.com and click on their garage sale link, then click on the "test and tune" link. The topmost meter, the digital engine multimeter, is discounted down to $15!

FyreLance

Sweet, thanks! I might just do that.

Riley's35089rs+

Sold Out...

FyreLance

doh!

Bralgar

Just disconnect the O2 and drive around, it will obviously throw a code but if it continues to run, hey it's pinpointed, and if it still dies, you didn't spend any money , but your still walking

FyreLance

Hehe, okay. I'll have to pull out the Haynes and figure out where it's at...

black89ws6

I've had the same MAF problem, but his is a 91--speed density system=no maf

Have you tried an ignition coil? When they fail, one of the first signs is failure at temp, unless your unlucky, in which case it just fails suddenly.

If you check your manual, you can diagnose the coil by checking its resistance across 3(i think) points. The book will give you a spec for it. I would check it once cold, and then let it warm up until it stalls, and check it again...or, if you have a spare, known-working one, swap it out for a test.

If you haven't done the ignition coil yet, I'll bet a dollar that'll fixit

black89ws6

you sure? I just went there and got one...

see:
This order is subject to credit card approval.
A formal confirmation with order number and
scheduled shipping date will be sent to you
within 24 hours or the next business day.


NAME = SEAN OETTING
ADDRESS = x
CITY = x
STATE OR PROVINCE = x
ZIP OR POSTAL CODE = x
COUNTRY = USA
DAYTIME PHONE = x
EVENING PHONE = x
E-MAIL ADDRESS = x
CREDIT CARD TYPE = x
CREDIT CARD NUMBER = x
EXPIRATION DATE = x
SALES TAX = 0.00
PREFERRED SHIPPING METHOD= UPS GROUND
SHIPPING CHARGE = 5.97


DESCRIPTION = CP7676GS DIGITAL ENGINE MULTIMETER
UNIT PRICE = $ 14.95
QUANTITY = 1
EXT. PRICE = $ 14.95


SUBTOTAL: = $ 14.95

SHIPPING METHOD: = UPS GROUND

SHIPPING COST: = $ 5.97

OHIO SALES TAX: = $ 0.00

GRAND TOTAL: = $ 20.92

TomP

Yeah, whaddya mean sold out? You guys didn't go under "Analog Testers", for the Engine Analyzer, did ya? No no no, I said to go under "Test and Tune", for the "Digital Engine Multimeter". C'mon now!

(If you've got a MAF, go for the sensor tester too, works like a charm! Sunpro released a model after that one which does more, so the old one goes into the bargain bin!)

Riley's35089rs+

I was looking at the wrong Item..Analog Testers

--------------------------------------------------------------------------------

Engine Analyzer - CP7675 Sold Out!

sorry about that