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Okay I installed all of the 4G37 parts this past summer to fix a shot ECU. Now as it is severely cold here in Wisconsin, my car is really hard to start, sometimes it wont start at all, and when it does, I have to keep some throttle in it so it won't die at stop lights and at idle.

Bad ECU again, or is it something else? I'm thinking that it might be the coolant temp sensor. Because I often have to mess with the throttle to get it to start.

Could be either a bad/dieing MAS sensor or the idle screw in the throttle body is turned too low. Does it act normal under wide open throttle? Usually if the MAS is bad it runs horrible when you floor it. Any check engine lights?

Do the coolant sensor first.

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Had a:
1991 Eagle Summit ES Hatchback - 4g15 12v 5spd
1991 Dodge Colt -4g15 12v 4spd
Have a:
1978 Oldsmobile Cutlass - 468BBO TH350
Round 3:
1990 Dodge Colt-4G63T 5spd

Yea, it acts fine under WOT. There is a crack in the exhaust manifold so it sounds a little off when the car is sitting in one spot, but under load (driving) its fine.

I'll pick up the temp sensor today and probably some plugs just in case if they are fouled, but I highly doubt it.

Got the sensor, put it in and the improvement is marginal at best. Still hard to start, and will die if I don't keep my foot in it at idle.

Did you try the idle screw yet?

it idles high as is. when I swapped all the 4G37 parts over, it idled like shit so I adjusted it then. Right now when warm its about 1300rpm or so, any less it would sound like its missing.

Oh, its also running premium with timing advanced all the way. should I back it off some and run a lower octane?

I think it could be the MAS. Do you have any extras to test with?

No 4G37 ones. Just my old 15, and I would have to swap the whole backing plate over too, cuz I only have the one. And even then my results will be skewed because it will run rich.

Uhhh, hello? This is kind of an urgent issue because it will just not start now. I have to park on the street and change sides every day, including weekends. So it needs to be able to move, and I can't push it that far in the snow.

Fouled plugs? if they were, I doubt the brand new NGK ones I just put in are. Still nothing.

Popped open the ECU and looked at the board, guess what I found? Absolutely nothing.

Not the coolant temp sensor.
Not the ECU.
Not fouled plugs.
Most likely isn't the MAF.

It is getting fuel, cuz when I pulled the plugs to inspect them (before I went to get new ones), they had fuel on them.

How did you adjust your timing? Have you done a compression test? First things that happen with a dieing ecu is idle issues and then hard/no start. I'd try another ecu, even if it looks ok it might not be.

_________________
Had a:
1991 Eagle Summit ES Hatchback - 4g15 12v 5spd
1991 Dodge Colt -4g15 12v 4spd
Have a:
1978 Oldsmobile Cutlass - 468BBO TH350
Round 3:
1990 Dodge Colt-4G63T 5spd

Uhh, I adjusted the timing by turning the distributor. And who said I have another ECU? I'm gonna need another one now? Great. And if that doesn't work, I would be wasting who knows how long: 1) Searching for another GOOD one, and 2) getting it shipped to me.

I'm currently driving my father-in-law's Dodge Ram. Gets about 9mpg, and I have a 25mile round trip for work. I need the Colt back!

What degrees BTDC is it set to and did you ground the ECU wire at the firewall to start the process?
Is the base idle set per the FSM?
Is your TPS sensor dialled in following the setting of the timing and idle?

You should start with all that if you have not done parts of this properly, because it sounds (this may not be the case) like you didn't use a timing gun or the factory procedures which must be used in order to zero the idle air controller, set base idle and timing. Your car will idle like crap and probably be hard to start if any and or all of these weren't preformed properly.

You do know you live in the same CITY as me?

A bad ecu won't have any visible indication of problems.

We get that it is an urgent issue for you, but realize we aren't Dodge/Mitsubishi's second warranty for you. We are responding to you with our extra time and effort, we could be spending with family or surfing for porn. If we can't get to you in time or you don't like our answers, Johnny auto repair is right down the street for 40-80/HR.

You sir have one of the 3 hardest to diagnose problems, my car won't start, hard starting, or I have this intermittant issue....

We can just give you ideas, that you may have not tried. Like the same thing happened to me when I got bad gas from and Indian community. It took 2 tanks to have it stop bucking and quitting on me. It could be your fuel filter, plug a fuel gauge up (20$ usually from local parts place) and see what it reads under load, or just replace the 10$ fuel filter. It could be a bad distributor cap(sometimes if you take a dull knife and lightly scrape the first layer of carbon deposits off this cures the issue) . It could be a clogged air filter. Could be your plug wires.

Try the cheap fixes first, but you should have already replaced your sparkplugs and checked your distributer cap and plug wires at least every other year. Or if you have had it for less than 2 years you should have checked those things in the first place.

And I don't know how many times I've said it, if you have a 3g CSM, you should problably have a spare (known good) ecu laying around at all times for troubleshooting.

PM LILEVO and see if he will help you out. and while hes at it he can make your car AWD, with one hand tied behind his back, and with no powertools.

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