I have a weird no start that only happens occasionally. If I turn the key and the check engine light is not on the car wont start. If it is on the car starts fine, The checke engine light never stays on, either. Any ideas?

Hey Phil can you message me or email me? chaseryan13atgmaildotcom

Have tried "jiggling' or moving the ignition key a bit left and right when it is in the on position and the check engine light has failed to come on?

Chances are the power to the cluster to illuminate the warning lights is on one circuit, but when grasping for straws....
--
Any twenty minute job is just a broken bolt away from a three day ordeal

Hi Philvo,

Most likely cause is the 25 amp fuse that's in a holder near the battery. Remove and clean the contacts.

Peter

If the power through the 25A fuse is interrupted, the CEL will not light during lamp test. In an automatic transmission 89, there should be 7 lamps with key on engine stalled. If the 25A fuse is removed, there will be only 6 -- the CEL missing.

The wiring to that fuseholder is the weak point, not the fuse. To test it, and its complete circuit through the system half of the fuel relay, to the engine management electronics under load, check for battery voltage at the orange wire on the AMM with key on:


--
Art Benstein near Baltimore

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how old is the battery ?

Hi Philvo,

Most likely cause is the 25 amp fuse that's in a holder near the battery. Remove and clean the contacts.

Peter

Hi,

This maybe a signal from the ECU in response that it is sensing low battery voltage supply.
This feature is built into a line of ECU program.

It not coming on at all is not normal, but the lack of light, it appears, can leave a light off.
This probably means the ECU is not turning on either and consequently a no start!

It coming on and then acting normal is explainable but traceable not so much!
This could be a problem with a older battery but since it’s cranking this points that is a different system.
So, its more likely back to a supply voltage reading or lack of, coming into the ECU.

Most likely it’s Corroded connections causing a resistance and that is what drops the voltage.
Since it’s temporary each time this is a nice warning sign! GOOD!
It’s even nicer that you are so observant!

When I say connections it’s either on the fuse(s) positives side or on the grounds.
The grounds are one half of everything in the car let alone each component.

Starting with the two off the battery.
One to the engine block and the other to the body of the car.

The fuse panel inside the driver door hinge area has numerous fused circuits each with two clips holding the fuse. This area of a void stays colder due to the mass of the door post metal behind it.
Corrosion is known to be a problem in this area due to moisture coming off the floor mats from rain or snow off of the feet.

What you need a blanket method to find it! More like a fine sandpaper blanket. (:)

It is good maintenance to periodically remove all the fuses and clean both ends of the fuses and the spring clips until shiny. Give everything a smear of anti corrosive salve or a light spray dusting of something made for this purpose to thwart moisture contact.
Doing this throughly will make it last for several years.

If this doesn’t help,
Check under your floor mats for wetness on both sides of the car in case you have a windshield leakage or wiper motor grommet dripping or water from the AC drain pan.
Sometime a rubber duck bill valve in the bottom above the transmission get clogged from leaf debris.

Like I said, it a connection and hopefully in the normal places to look.
This will catch some other electrical gremlins, sitting on the side lines.

They get around, rubbing their grubby little green hands together, all while doing their Jim Carrey grins!

Phil

Thanks Phil,
I have replaced almost every sensor and electrical component under the hood as well as a 951 White Label ECU, updated ICU, FP relay, AMM, crank sensor, Ign. Amp and Ignition components, coolant temp sensor etc...I did clean the grounds from the (-) battery and the two at the fuel injectors on the intake. I will switch out the fuses and check for corrosion. I agree it's a missing signal as I cant check any codes when it does this. and the check engine light wont be on when I turn the key to 'On'.
I will let you know how I make out, Phil

TP31361/1 is a useful document to have when dealing with faults in the LH2.4 Jetronic fuel injection system, it can be found here.

Section E4 has some procedures to check the diagnostic socket. I would probably start with that if fault codes can't be read.