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88 LH2.2 Chrysler ignition. What can I do to it?

HiSPL

Fanking Champion 1993
Joined
Jan 8, 2015
Location
College Station, TX
My car is developing a really bad miss. Its like total spark cutout. A month ago it would happen once or twice a week, but it's been getting steadily worse. Its like when you hit the rev limit, but it can happen at any rpm. Never happens at idle. Typically when under acceleration and light loads.

I have new plugs, wires, cap and rotor. All the good stuff. I have never messed with any other part of the system.

What could the issue be? The ignitor box? It doesn't "feel" like a coil issue to me, but idk.

If I have to load up the parts shotgun for this, what can I do to improve the system? The way I understand it I can't move to the Bosch EZK since I'm NA (unless I get one flashed?). Is there some kind of hot rod parts I can use instead?

Idk. Help me spend money....
 
LH2.2 n/a 8v 700s came EZK & in ?88 would have had the same fuel ecu / other fuel components otherwise?

There isn?t much to it, Dave Barton sells a harness for an LH2.2 conversion to use the same year EZK that the 700s came with, but I wouldn?t bother with that if you got some GXL wire, proper tools and good ?88+ fuel harness anyway, even if I wanted to convert to EZK?

There?s a TSB about shims used on the pins of the mopar box plug on the wash bottle?
This said, the ?88+ type mopar box & updated harness seldom gives trouble?
Sometimes on the hot weather cars the spring in the map sensor gets weak but there again, the ?88+ cars are less prone to it.

A handful of the mopar cars used that style box after ?88 to control spark only (like horrific smog laden AMC carryovers w/carburetor in the late Chrysler acquisition phase?been a while since I took one apart from the junkyard?) , but not many?
Idk if the Bosch EZK was too costly for the stripper 240 model or why exactly Volvo kept sourcing that part from mopar?

If you?re going to install the LH2.2 version of Bosch EZK verify that the hall gate pattern is compatible/equivalent to the one in the ?85-?88 700 donor?
Most of those used head mount dists those years and I forget which of the various 240 dists works correctly with those?the mopar ICU no seem to care about hall gate pattern?doesn?t seem that precise, but it matters with EZK.

Also of note is the knock detection, despite the Bosch EZK used with 2.2 only having 2 or 4 hall sensor gates for crank angle resolution is a lot more precise as is extreme high or low temp &/or barometric pressure.
The knock detection is much more sensitive and excludes portions of crank position where knock can?t occur, even with early 2-4 gate hall sensor early EZK compared to the mopar ignition.

That said, on piston slappy B230 models I?ve had the slap cyclically trigger the knock detection & cause poor fuel economy at cruise on an engine without any other faults or blowby etc?
Coating the pistons and adding squirters cured it. Same engine and everything else, .17c/hr?

On the mopar ignition cars the ignition knock detection is pretty basic?the right sharp body hammer next to the knock sensor on the block & the ecu retarding the ignition timing is observable off idle?

Sometimes it?s faster /seems easier to engage in swap-tronics, embark upon a conversion &/or fire the parts cannon/shot gun approach & see what sticks , and to a degree it is?I can and have and I?m totally can relate. but if you don?t also properly isolate It you might not exactly know what resolved it?

Intermittent is tough?
I?d keep looking, especially if it had the updated lard ?88 mopar box and harness but they?re all old by now so never say never for a failure, either?
It?s probably something stupid like a crimped terminal, throttle position switch or electrical load with a crusty wire or fuse or something getting yanked on under load with the usual flexy 240 motor mounts but if not that test the map sensor on the box and examine fhe plug & board on the mopar box and verify it?s the correct part # for the year/harness & engine and no one swapped the wrong one in?
 
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like when you hit the rev limit

When dark outside, open the hood with with a warmed up engine running, and rev up engine. See any light/spark/etc.

Clean and check all grounds....disconnect battery, and pull ECM's plug, and clean plug side with contact cleaner(Example: WD-40 Specialist electrical contact cleaner ), then replug back in when dry.

Not suppose to remove plug from Mopar box. But if done, I'd use contact cleaner on both sides, and then use dielectric grease on plug side.

>Never happens at idle

Suggestive of some type of electrical issue...not enough current flowing like to injectors or coil...and/or the wires feeding power or ground sides. Hence the above suggestions.
 
There's one vacuum hose that goes to the Chrysler box...is it in healthy condition?

Other than that, I'd start looking for a 740 EZK donor and make the ignition swap. Its easy and effective
 
Will a turbo EZK run on an NA?

yes, but retarded.

Ignition mapping is different turbo vs na. Wiring is effectively the same. You can find a NA car no? There's a NA 740 out here in the yard...if ya need something very particular.
 
yes, but retarded.

Ignition mapping is different turbo vs na. Wiring is effectively the same. You can find a NA car no? There's a NA 740 out here in the yard...if ya need something very particular.

I didn't know if it ran more retard when out of boost, but makes sense I guess.

Just asking because I have a 740 Turbo in my driveway. As soon as the insurance settlement is done I'll be parting it out and saving as much as possible. I guess I could use the wiring and buy the EZK.
 
When dark outside, open the hood with with a warmed up engine running, and rev up engine. See any light/spark/etc.

Spray bottle with water can help detect any stray sparks as well.

Wiggle the electrical connections a bit with the engine at idle, this can find intermittent issues with corroded or loose plugs. My old '87 had complete cut seemingly at random - turned out to be a loose plug at the distributor sensor which was making or losing contact. Gave it a good purge with contact cleaner and re-assembled tightly with dielectric grease and that cleared things up.
 
I have new plugs, wires, cap and rotor. All the good stuff. I have never messed with any other part of the system.

What could the issue be? The ignitor box? It doesn't "feel" like a coil issue to me, but idk.

How about the pick-up in the distributor if your model has that, or the crank position sensor?
 
I highly suggest cleaning all grounds and hot sides first.

I've never heard of ECM-Ignition "computers" failing this way.

Question is which side (fuel, ignition) is failing. When throttle is depressed, more fuel is required, and if ground/hot sides of injectors are iffy...stuff happens.

I assume your throttle cable is fit for duty...not hanging up. Have someone slowly depress throttle pedal to floor, then slowly release throttle pedal while you watch throttle linkage under the hood.
 
I highly suggest cleaning all grounds and hot sides first.

I've never heard of ECM-Ignition "computers" failing this way.

Question is which side (fuel, ignition) is failing. When throttle is depressed, more fuel is required, and if ground/hot sides of injectors are iffy...stuff happens.

I assume your throttle cable is fit for duty...not hanging up. Have someone slowly depress throttle pedal to floor, then slowly release throttle pedal while you watch throttle linkage under the hood.

Has to be ignition. Its a hard and quick miss. Like you hit a pothole that jolts the car then its back to running just fine.

If it was a fuel miss it would bog momentarily and be a much gentler experience.


I will have time to look at it later this week. I'm coming to the end of hell month for me at work.

I've been leaning towards maybe the throttle position sensor. It seems to only happen at cruise under a very small throttle opening. Basically where you keep the throttle at 90% of the time you are driving.


I figure I'll go through the idle and TPS adjustments this weekend, clean and spray all connectors and check vacuum lines this weekend. If I don't find something wrong doing this I may actually have to load up the parts cannon.
 
KJet "Idk if the Bosch EZK was too costly for the stripper 240 model or why exactly Volvo kept sourcing that part from mopar"

This is the question which keeps me wake.

Between 88-91 Volvo was using K-jet, L jet, Mopar, Renix, Lh 2.2, Lh 2.4. EZK, distributor style. All this on redblock.
 
I went through random missing and chugging on my friends mopar ignition 82 with kjet. It finally turned out to have intermittent pins in the connector from the unit to the distributor. We got it fixed and then after a few months the hall sensor failed for the second time in a couple years.

So, we converted it to reliable Bosch breakerless ignition and it's been fine since then.
 
Its a hard and quick miss.......pothole that jolts the car then its back to running just fine....TPS adjustment

My 1990 240 LH 2.4 does this around idle throttle plate position...at a little throttle position sometimes, and then get a Jack Rabbit acceleration...when cruising along, same issue but just the opposite reaction, deacceleration. Depress throttle a little further down, issue gone.

Just a guess here...Timing is being advanced

One of these days, I'll fix it. Vehicle mainly used for cruising

Remove TPS's plug, and drive on for a test.
 
google up the ignition troubleshooting flow chart and go through it, preferably when it's acting up. In my experience cleaning the connector at the ignition computer, and then using a pick to re-tension the bullet connectors before putting it back on with one straight fluid motion and using a zip tie to secure the connector to the box has cured some symptoms I was having that are like you describe. I also remember having some issues with an lh2.2 car that were from the connector for the knock sensor coming unsoldered.
 
Finally had some time to mess with this thing. I assumed I had the Chrysler ignition, but I guess not?

Anyway, is this hall sensor connector supposed to be all wiggly like this? I can't get it to cut out by wiggling so I guess its alright, idk....

 
NM, it's a Chrysler module but with the Bosch style connector at the hall sensor.

Probably normal for an 88, but I read "Bosch" on the trouble shooting chart and got excited for a second.


I cleaned and reconnected all the plugs. Most were in fine shape, but the 2 pin plug that goes to the coil fell apart. Its well together now, and still no change. Only thing I see is that wiggly connector for the hall sensor. Or maybe its the hall sensor itself, but being pretty internittant I;m not sure how to test it.
 
Doesn’t necessarily have to be spark. Low fuel pressure can cause similar issues. You check fuel pressure? I had an intermittent issue that I thought was spark, turned out to be fuel pressure. I had to leave a gauge hooked up to my fuel rail for a week to catch it in the act.
 
Doesn’t necessarily have to be spark. Low fuel pressure can cause similar issues. You check fuel pressure? I had an intermittent issue that I thought was spark, turned out to be fuel pressure. I had to leave a gauge hooked up to my fuel rail for a week to catch it in the act.
Could be I guess, but its a HARD cutout. Like motor mount ripping neck snapper.
 
I had an 87 where the coil wire was making a poor connection at the firewall connector. it had similar symptoms, it would randomly die. but on an 88 you wouldn't expect to see that. my guess is you have a dying coil/powerstage or weak connection somewhere.
 
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