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Misfiring on cold start.

It seems to revv like **** and almost like its being held back, or missing as I try to hit the gas. I always stop hitting the gas because it seems terrible for the engine...but it does seem to be okay after rev it up one good time..

And its definitely only after it sits overnight or when I'm at work, 10+ hours
 
Cylinder drop test?

If you mean pulling individual injectors, each one made it run 10x worse. I noticed that it doesnt run rough until you press the throttle. As soon as air starts moving it like chokes out. Of course this is until the temp gauge starts moving.
 
In the next few days ill check my fuel pressure on cold start and ill learn how to test the ECT.

I've changed injectors from stock to cleaned t5 ones. Theory was a sticky injector, but I guess not.
The car had a CEL for the ECT when I got it, a brand new sensor I got from FCP was defective or something so I pulled a junkyard sensor and harness
 
I have swapped it already with one from the jy, and it doesnt have a fuel smell out the vacuum line, but I know that doesnt mean anything. Ill try reading the pressure soon see what its looking like.


First one I broke gave 5 bar pressure. Nothing came out from vacuum or return line. Second that I broke barely hold 2 bar pressure on idle, and giving throttle did nothing to fuel pressure.

Anyway, in both cases car was extremely hard to start (black smoke) and light hesitation on few first miles. HC was high on annual emission control, (60-70 Ppm) when I usually get under 20. Lh 2.4 is darn good fixing small faults by itself, I guess.

I got pressure gauge with T-fitting (Ermeto L8 size) but you can easily measure pressure with tire pressure gauge from Schader valve
 
My wagon does seem to clear out a bit easier than that. It has the efi like you. Usually it is the winter weather when mine starts like that. Now that summer is here the cars don't run chunky like that when cold.
 
I also have a different, maybe not so different problem while cruising. I have another thread about it, but maybe there connected? It only happens at 10 in hg of vacuum and an interminnent rich spike/misfire. Its very annoying, and for as long as I've owned the car these problems have been there. Even thru an engine swap...

Symptoms of hopefully the same issue...
Cold start bogging/missing

Even when warm 75% of the time any throttle input puts the afrs into the 11s and its not quick off the line...it recovers to 14s fast but I believe it shouldnt do this.

While cruising at 10inhg and light throttle, just keeping speed, random stumble and afrs drop to ~11 and recovers.
 
Intermittent problems are tough unless you catch them in the act. Probably just start with going over things like connections to sensors, grounds. Look for any sneaky vacuum leaks. Maybe try some component substitution like a different air mass sensor?
 
OP double check that all grounds are perfect. Remove the bolt that squeezes the wires to make the ground. Polish up the connector. Reassemble. Replace fuel system relays. Replace the fuse and take a long look at the fuse holder.
 
I also have a different, maybe not so different problem while cruising. I have another thread about it, but maybe there connected? It only happens at 10 in hg of vacuum and an interminnent rich spike/misfire. Its very annoying, and for as long as I've owned the car these problems have been there. Even thru an engine swap...

Symptoms of hopefully the same issue...
Cold start bogging/missing

Even when warm 75% of the time any throttle input puts the afrs into the 11s and its not quick off the line...it recovers to 14s fast but I believe it shouldnt do this.

While cruising at 10inhg and light throttle, just keeping speed, random stumble and afrs drop to ~11 and recovers.

I'd put meter on the TPS signal and see if it's jumping around.
It should make a smooth transition from low to high as the pedal is smashed.

I'm thinking the signal looks like a saw blade and the ecu gets confused thinking you are jacking off the throttle?
 
Okay guys, ill definitely give a good look today. After work I will clean grounds again, inspect my hoses for tears/spray some more carb cleaner everywhere.

Ive replaced the fuel pump relay but also have a spare OEM one ill try. Would you suggest swapping the RSR?
My brother also has his 016 amm that he'll probably let me try out. I've got another knock sensor to try also.

I'm definitely a noob when it comes to using a meter, while measuring the TPS, is there only 2 wires that exit it that I would probe? Would the car need to be running? Or the ignition just in the ON position?

Also going to take a look at fuel pressure when I go to leave.
 
Cool, I checked to see if it was adjusted properly and it clicks as soon as the throttle opens.
Will get back hopefully tomorrow with something helpful
 
I tested my AMM with a meter a few mins ago, I followed brickboard instructions. First checking ground, ohms between terminal 1 and ground is .8ohms, it says it should be 0.0 ohms. So bad ground?

Next it said to start engine, probe terminal 3 and ground and you should get approximately 2.3v. Mine is 3.1-3.0 volts.

Sooo, am I looking at a bad AMM because of the second test? Or just a bad ground causing the volts to be wrong?
 
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