'94 Cranks But Won't Fire Up

[Instakill]

Hi please help. I am out of ideas...

Got into the truck to drive one day and she died on me. First she idled fine, then stalled when I put the transmission into drive. Now she won't start at all. The engine cranks but won't fire up. I have spark on 1-4 and I have fuel pressure up to the rail. I've tested resistance on all of the sensors and injectors (within specs) and I haven't found a blown fuse or link. My suspicion is that the ECU is toast, although I can't see any visible flaws in the circuitry. I have no codes popping up, and when I go to check the diagnostic harness it reads only that the ECU is functioning normally. I have an extra ECU from a 95 MM M/T but I don't think it will work in an auto. This is driving me nuts!

What else can I try? Why does she turn over but not start?

1994 MM 2.4 Auto

[BradMph]

Welcome to the Forum

Looks like you checked the norms, Electrical, Fuel, Mechanical.

Hang in there, someone will be along that might be able to give you help with that issue.

[royster]

CSS

Check Simple Stuff.

Check your vacuum lines for leaks. Check the timing mark alignment with distributor cap position. You said you checked sensors, did you check the Throttle Position Sensor?

Hope this is at least supportive, and welcome to the forum. Be sure to a.) post pictures! and b.) let us know the progress/resolve.

scan0001.jpg

[geezer101]

Hi Instakill, check your timing marks - if the belt has expired it could've stripped a tooth or 3. It'll still turn over but no way will it fire. It is one of those things you have to stay on top of as far as regular preventative maintenance goes. The fact that it still turns over and isn't throwing error codes all over the place indicates it's gotta be something relatively small.

[Instakill]

Hi Instakill, check your timing marks - if the belt has expired it could've stripped a tooth or 3. It'll still turn over but no way will it fire. It is one of those things you have to stay on top of as far as regular preventative maintenance goes. The fact that it still turns over and isn't throwing error codes all over the place indicates it's gotta be something relatively small.

Well I actually got her to start up and idle for a minute, but as soon as I opened the throttle she stalled. The idle was rough and she surged a few times; CE light was flickering too. Unfortunately I couldn't get any codes from it. Now she won't start again. The truck literally went from running perfectly to just quitting on me without warning. Makes me think the ecu or the relay failed, but I don't know how to test these things.

TPS was one of the first things I tested and the resistance was within specs.

I pulled the valve/timing cover and the timing belt (1) still has good teeth in the camshaft pulley and it isn't worn out. I didn't check the 2nd belt though. I will double check the timing marks.

I ended up putting an ecu from a m/t in it but it still won't start. I've ordered an ecu for an a/t and hopefully that fixes it. I don't know what else it could be.

[royster]

Not sure about a '94, but for the '90, the timing mark on the head is as follows:
scan0038.jpg
Making sure #1 is TDC and this mark is lined up, check the crank pulley mark, and the distributor position to assure they're all right on, together.

Though the teeth might not show wear, it is possible for the engine to slip a tooth or three (as geezer puts it) and this simple test will show you if this has occurred. To slip timing would be rather instantaneous, which could explain a few things. I suspect the surging is the ecu trying to sort things out, but if the timing's off, there's no way it can succeed.

This is assuming yours' is a Mitsubishi: your array says "other" in regards to engine.

[lush90]

If the ECU has never been rebuilt, that would be my best guess. When mine went out, I was sitting at a stop light and it died. Eventually restarted and was able to limp home, after which it would not start. I swapped the ECU from my 91 and it started immediately. I used Foreign Auto Computer Repair in FL and was very satisfied. It took less than a week and cost about $200., but that was for a 3.0 V6.

[geezer101]

I don't think you can use a M/T ECU module on an auto equipped drivetrain as the ECU interfaces with another unit running off the transmission. If you you can put your hand on the ECU case and it feels hot that will be an indication it is fragged. I had one die on me in a different car and when it failed it went into limp mode - I put my hand on the case and it was hot enough to fry an egg...

[Instakill]

I thought so, but I wasn't sure if a m/t ecu would prevent it from starting. My ecu is factory and it looks mint, and the capacitors seem fine. However I doubt I'd be able to spot a short or bad connection in the circuitry. The engine to firewall ground wire in my truck had come loose, so I wouldn't be surprised if a bad ground had shorted it out...but I don't even know if that's possible because the ecu harness has its own ground wire to the case bolt.

New ecu gets here in a couple days. Hopefully it works.

[geezer101]

I think you can fool an A/T ECU into running a M/T optioned truck but not the other way around. Hopefully the replacement ECU will fix the start issue and you can get back on the road.

[Instakill]

I think you can fool an A/T ECU into running a M/T optioned truck but not the other way around. Hopefully the replacement ECU will fix the start issue and you can get back on the road.

Well, no go on the ecu. Truck still turns over but won't start. Any more ideas?

[royster]

Did you verify the timing marks on all the crucial points, to assure you didn't slip a tooth on the belt? Did you make sure the distributor is in the right position?

[Instakill]

Fixed it. Although I had spark, I threw in new plugs and it started up. I really thought the ecu was the problem, since it seemed to just die without much drama or reason; no stuttering or misfiring or anything...but hey I'm glad it's fixed. Now to fix the engine ticking. Not sure if it's a sticking lifter, bent push rod, worn rocker arm, or weak valve spring but it comes and goes with the pressure and viscosity of the oil. Any tips?

[royster]

Again, with no engine specified, it's difficult to give a difinitive answer. However, if it's original to your truck, it doesn't HAVE push rods, so we can eliminate that one.

If it's a 2.0 it could be an adjustment. If it's a 2.4, likely the lifters (located inside the rocker arms) are worn. A little Mystery Oil will help temporarily. A good oil flush and change might help, too. Though controversial on this website, I recommend a few ounces of Sea Foam in the crank case before the oil change, and drive it a few miles. Drain the oil as soon as the engine stops. That way ALL the gunkus~funkus can drain out. (Letting the engine cool down allows crap to settle and possibly not drain out).

[geezer101]

We don't hear anything about "sea-foam" here in Australia, but I have an option that my fellow mitsu fiend put me onto that works. Diesel fuel. Now, if you are anything like me you are envisioning catastrophic bearing and ring failure at the very idea of this but I can guarantee that this will work as good, if not waaay better, than the stuff you pour into your engine to flush it out for $10+ or whatever the auto shops charge for it.

Buy a little diesel fuel, the engine oil you intend to use with a new filter - and some cheap ass engine oil (I'll get to the reason why later).
Get your engine up to operating temperature, then dump about 1/2 a litre of your engine oil into a drain pan and replace the sump plug. Add 1/2 a litre of the diesel fuel into the engine and run it for 5 minutes (go for a lap around the block to get it squirting through the galleries and any hydraulics) then dump the whole lot while hot. Now, remove the old oil filter and drain it as much as possible, then refit it (if you use your new filter at this point you will contaminate it and subsequently cross-contaminate your new oil and filter later). Add about 2.5/3 litres of the cheap ass oil to your engine and run it again for 5 minutes (this will mix with any remaining contaminated oil in the sump and the oiling system and get it into a suspended state) and then proceed with your usual oil and filter change. The amount of gunk you will get out of your engine from doing this method will surprise you if you have never performed a full flush before, and it will ensure your new oil and filter will perform at it's best for longer. I would recommend doing a flush using this method if you have never done one before - I did it on a car with over 240,000 k's on the clock and the engine oil still looked like it was just poured out of the bottle 500 k's later. You waste a few bucks on cheap oil but the cost of the diesel fuel flush is more than adequate to offset the outlay.

(*if any board members thinks this is suitable to be re-posted somewhere more appropriate, feel free to cut and paste...)

[royster]

I took the liberty of re-posting this on "Why Didn't I Think of That?", Geezer. Good tip!

[pennyman1]

5 minute motor flush is really nothing more than diesel fuel for a lot more money. Not a big fan on motor flushing a high mile motor - do that on an american motor and you will find out how bad the bearings really are...

[Instakill]

Wasn't sure whether to post a new topic for this or not, but since my little no-start incident I've noticed the truck has a slight misfire - a hiccup really, and not big enough for the CE light to register (if it would) - and it only happens under load (in drive/rev) and only at idle. I can't figure out what's causing it. I changed the plugs and wires and ran seafoam through the oil and gas but it hasn't fixed it.

Any idea what this could be? I've read that carbon buildup could cause this, but I'm not so sure that's the problem.

It wasn't doing this before the truck died. It just started after I got the plugs and wires in. Of course, I nearly took the whole truck apart trying to figure out why it wouldn't start but I don't *think* I broke anything.

First I used some NGK platinum plugs I had laying around and it started up, but later I changed them to NGK BPR6EY 11 plugs (although my manual specifies NGK BPR6ES 11 plugs, I could not find a store that carried them). I had NGK wires in but I put on Duralast wires just to see if they helped, but I still get that misfire.

Is there a big enough difference between v-power and standard plugs? What else could cause a random misfire?

Thanks!!!

[pennyman1]

clean the egr valve and passages, and the pcv too. If you have a hand vacuum pump, check the vac advance with it to be sure it isn't hanging up. Check the bolts on the intake and throttle body and tighten if loose.

[Instakill]

CE light is not on, but I hooked up my multimeter and got a #1 cyl TDC code. Manual says to check harness and replace distributor components.

Where is this sensor located? Manual points to the ignition coil. Is it inside the distributor?

Truck will start right up but misfire randomly with a quick drop in RPMs from 750 to 400 then back to 750. Is this a timing issue? Or electrical?

[Instakill]

Went ahead and replaced distributor assembly. Truck is running fantastic now! Motor runs so soft I can't even hear it at a red light.

Next two questions:

1. Where can I find (new) decent body/frame mount rubbers?

2. The last place that aligned my truck left the steering wheel five degrees off left. Can I adjust the toe myself without f'n up the alignment?

Thanks

[camoit]

You can pull the wheel and just put it back on. That is all it takes to fix that.

[jospiv]

Well, no go on the ecu. Truck still turns over but won't start. Any more ideas?

fuel pressure reg? gas in the vacuum line? Let me know if you fixed it yet. I'm having the same problem,

[geezer101]

fuel pressure reg? gas in the vacuum line? Let me know if you fixed it yet. I'm having the same problem,

Instakill diagnosed the fault as a dead ICM in the distributor (ignition control module). ECU wasn't getting injector/ignition pulse signal. He opted to replace the whole distributor assembly which rectified the issue (didn't state if it was a new or used part...)