Teenager + GT 5.0 = HELP

[rockn]

Great forum and I need help.
My son has a 91 GT with only add on mods. He was in a wreck about a month ago (front end) and now is ready to go to the shop to get fixed. When cranking the car, it backfired, ran rough at idle, and had to keep the pedal down to move the car. I asked him what his guages said, and was told all were fine. When it blew fire out the back, I suggested timing slip. We put in new chain/gears (chain was loose but not slipped, no gears worn). New Distributor cap/rotor. Wires and coil fine. Fired up fine, but within a minute went back to same problems. When I interrogated : ) him, he admitted that his guages do not work from trying to put in white face, the battery light stays on, and a friend unhooked his battery while the car was running when it started all this. Will the codes still stay after the battery mess, and where can I start. I am an old chevy type of guy and MAP/stuff are a little new to me. Suggestions would be great. I can tear a motor to the bare block and back, but alot of this stuff is greek to me. Thanks......mp
PS...it ran fine after the wreck...

 

[squeeeg]

Were the guages before or after the wreck. I would guess that something got disconnected during the switch and not reconnected.

 

[RsStanG1987]

Has he had the car running for a while after the wreck. I had a problem like that with my car once. I replaced all the same things you did and the same thing kept happening. Try replacing the fuell pressure regulator. In my case i replaced that and everything else. The problem ended up being that the valves werent seating right, there was blowby on most of the cylinders and one injector was leaky. The effect was the car running rough fuel spilling into the exaust and then igniting and blowing the mufflers apart. I would take it to a garage and have somebody do a compression check on it and pull the codes. Thats just my .02

 

[rockn]

The guages were before the wreck, so it was running fine without guages.

 

[DMAN302]

Possible some vac lines were broken?hard lines are old and can break when moved, also make sure the intake elbo is secure and not allowing unmetered air after the maf sensor. Check timing, and check to see if you have plug wires hooked up according to the HO diagram and not just 302..book has both. Then check FP for consistancy..very hard call after car has impact because soo many things could have been damaged. Also check to see if Charcol canister is still intack and hoses attached..possible vac leak there too.

 

[jrichker]

Step 1.) Dump the codes and see what the computer says is wrong…

Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great.

See http://www.troublecodes.net/Ford/
OR
See http://www.dalidesign.com/hbook/eectest.html for more descriptive help
OR
See http://www.mustangworks.com/articles/electronics/eec-iv_codes.html

IF your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.

Codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.

Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.

For those who are intimidated by all the wires & connections, see http://www.actron.com/product_detail.php?pid=16153 for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Walmart.

Step 2.) Fix the items or post the codes and get some more help from the Forum members.

 

[2002BLGT]

where was it hit ???? passenger side ??? if so , probably cut some wires going to the MAF .....IMO......

 

[dastang2]

MAF is what i was thinking too

 

[50 4 Fun]

Yep MAF or Vac leak

 

[5spd GT]

I would get a few engine shots and post them on here and see if some of us can pinpoint something out of place...

Troubleshooting can become a pain...Good Luck

 

[rockn]

Will get some engine shots up tonight hopefully.
Thanks for all the suggestions, at least I'm not running in circles or throwing money at it.
Mike

 

[rockn]

Here are the pics and thanks for the advice

 

[Michael Yount]

I'm with richker - pull the codes and see how they help. However, if you've been trying to run it with the maf pulling through no upstream piping/filter/filter box, that could be throwing the accuracy of it's readings off. I'd try temporarily slipping the filter/box back on so that the maf sees the same type of air stream it did before the accident.

 

[5spd GT]

Looks like you got a new alternator atleast ...and where is the battery (mounted in the trunk/hatch?)...

Yeah atleast tape like a filter (since the body is a bit damaged...the box might not fit on right) to it to provide something for it to pull air thru...that fan or even the little alternator external fan might upstruct the air flow readings to be technical ...but just put a filter over it and try again and see if it helps...

Pulling the codes is always a good idea...

 

[HISSIN50]

i would not disconnect the battery with the car running. future reference.

i second the above sentiments about being sure the plug wires are set up for the HO order. also, ya sure the dizzy was not installed out of phase? it can run out of phase.

if the battery was disconnect for long, the KAM would be cleared. but if the car ran off the alt, codes might still be in there (the KAM retains some residual power after the battery is disconnected - one normally has to discharge it). JR's links for pulling codes would be my next step.

good luck.

 

[sweet~Low~93]

Great forum and I need help.
I suggested timing slip. We put in new chain/gears (chain was loose but not slipped, no gears worn). New Distributor cap/rotor. Wires and coil fine. Fired up fine, but within a minute went back to same problems. When I interrogated : ) QUOTE]


I had a 302 w/ timing slip problem, turned out to be a broken Bolt for the Cam
It would run fine, run for few weeks no problem then it would jump...

I don't think that's your problem.. unless he hit something really hard
Motor mounts look fine?

Try what other guys said. first.. Vac line or Filter air box hook up.
some 5.0's will not stay running without the air inlet pipe hooked up..
I had one


I hope he's ok. ?

 

[rockn]

My son is fine, except for the fact that everyone at his school is giving him grief for wrecking such a fine piece of american muscle (ricers are laughing he said), and his old man is a little dissapointed in him. The battery is in the back. He got his voltmeter in dash working, and it showed a discharge, took the alternator to Advance and they said it was fried (0 output) That is the new one he put yesterday. Still does not read as high as it should. I am going to take it today to have whole charging system checked and the codes pulled. I'll keep ya'll informed. Thanks for all the good advice and please let everyone know that battery disconnected while motor is running = voltage regulator/alternator not happy.

 

[ECU5.0]

just wondering...what part of NC are you from?

 

[HISSIN50]

Thanks for all the good advice and please let everyone know that battery disconnected while motor is running = voltage regulator/alternator not happy.

yep, think i mentioned that before. it creates a spike which can create havoc throughout the entire electrical system.

good luck with it.