Engine 87 LX won't run after warmed up

gtboost02 · Nov 27, 2020

hello all, i'm new to the site but have been into fox bodies a long time. here's the short description of my issue: i'm putting an 87 LX together from a shell. the car will start when cold with the idle being terrible, then when it warms up it just stalls out even with me riding the the throttle. when i first got it running and i drove it a couple miles it pulled hard and ran strong, but never could get a decent idle out of it. iv'e tried alot of the basic testing & what i think would be a possible suspected items. including swapping out the computer as well as the whole distributor and tps. has anyone had this problem before?

HemiRick · Nov 27, 2020

Know how to use a can of some flammable stuff to find a vacuum leak?

Haste347 · Nov 27, 2020

Have you gone through the checklist of verifying the idle w/o the IAB plugged in, TPS voltage, etc? 87's don't have mass air sensors, so they are more particular about the TPS being right. This also might have something to do with the o2 sensors as the cpu goes into closed loop after warm up.

General karthief · Nov 27, 2020

Several things can cause this, I would go through the 'surging idle checklist', you may discover multiple issues since this sounds like it's been put back together and you didn't acquire it already running,

Help me create the "Surging Idle Checklist"

Updated 26-Oct-2019 to clarify creeping idle RPM increase as the car is being driven. Many of you are familiar with the "Cranks OK, but No Start Checklist for Fuel Injected Mustangs" checklist and the No Crank Checklist. They are very effective in finding and eliminating the problems by use of...

forums.stangnet.com

This will show you the proper procedure to test sensors and check for codes, set idle and other things. Do the list step by step, don't skip around, the next step depends on the one before, it also keeps you from chasing you tail and just repacing random parts hoping to resolve the problem(s).
There are lots of info in the technical/how thread in the sticky section in the tech forum where experienced members have been there done that and show how to fix it.

gtboost02 · Nov 28, 2020

sorry to say, it WAS converted to mass air by someone previously. i'm going to check for codes, that's one of the only things on that list i didn't go through. i'm also going to try an old school thought and change the coil out. i did most of the other tests. ALSO it was smog deleted as well. i'm sure of one thing by the way it ran when i first got it running it not a cracked piston or stuck valve.

General karthief · Nov 28, 2020

gtboost02 said:
. i'm going to check for codes, that's one of the only things on that list i didn't go through. i'm also going to try an old school thought and change the coil out. i did most of the other tests.

This tells me you didn't do what the directions stated in the checklist.
Look, with the problems this car has you have your hands full so you have to be methodical in diagnosing all the issues because believe me, you have a few.

Potomus Pete · Nov 28, 2020

The module on the distributor goes bad as it heats up. Then goes bad all together.

gtboost02 · Nov 28, 2020

yes i do have my hands full. now it will crank but won't start at all, so i'm going to start with the cranks but no start list.

gtboost02 · Nov 29, 2020

got it running. was pinched fuel line

Decipha · Dec 1, 2020

pinched fuel line will restrict fuel flow and cause lean out at wot which is the #1 cause for engine failures and a perfect way to grenade the engine

hence why you should never go WOT when you have mechanical problems or if the vehicle is not running correctly. As you stated it pulled hard that was guaranteed to be damaging the engine ever time you got on it.

gtboost02 · Dec 1, 2020

it wasn't pinched then. it's all good now. no mustangs were harmed in this post

General karthief · Dec 1, 2020

'if it ain't running right rev it up!!
That 'al fix it.

Mustang5L5 · Dec 2, 2020

gtboost02 said:
it wasn't pinched then. it's all good now. no mustangs were harmed in this post

We need a video of a smokey burnout as proof.

7991LXnSHO · Dec 2, 2020

Going step by step through the surging idle checklist will give it a thorough electrical physical. You might be surprised how much better it can run and what Hackery you can correct.

Engine 87 LX won't run after warmed up

gtboost02

Member

HemiRick

I'd be looking at jacking under the house

Haste347

Member

General karthief

wonder how much it would cost to ship you a pair

Help me create the "Surging Idle Checklist"

gtboost02

Member

General karthief

wonder how much it would cost to ship you a pair

Potomus Pete

I'm still waiting for the fully nude shots

gtboost02

Member

gtboost02

Member

Decipha

Active Member

gtboost02

Member

General karthief

wonder how much it would cost to ship you a pair

Mustang5L5

That is…until I whipped out my Bissell

7991LXnSHO

wanna catch the space herp

Similar threads

Engine 87 LX won't run after warmed up

Member

I'd be looking at jacking under the house

Member

wonder how much it would cost to ship you a pair

Member

wonder how much it would cost to ship you a pair

I'm still waiting for the fully nude shots

Member

Member

Active Member

Member

wonder how much it would cost to ship you a pair

That is…until I whipped out my Bissell

wanna catch the space herp

Similar threads

Privacy & Transparency

Privacy & Transparency