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Major problems after RC 750cc injector install *HELP*

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ILLiCliPSE

20+ Year Contributor
1,576
3
Jan 11, 2003
Boynton Beach, Florida
I recently installed some RC 750cc injectors that my bro got me for my birthday. The car ran like crap, but it was drivable. I drove it to work for 1 day, and the next morning, the car doesnt start. I looked for anything that could have been wrong and nothing was working. The car was cranking but not starting. I came to the realisation that my rc 750cc injectors might fried my eprom, since theyre the wrong resistance(?) since theyre from an SRT-4. Remeber, the car was running fine before I installed them, and after the install, the car ran like crap for a couple days, then didnt start the next morning. So, I swapped the stock injectors back in, and it still didnt start. Then I swapped the stock ecu in this morning, and it stared and runs perfect. Now, if I leave the car off for a certain period of time and try to start it again, the car cranks for a while, then finally starts. WHAT CAN BE WRONG? It was doing this before the car died with the eprom ecu...cranking for a while then starting. I hope the same thing isnt happening, and Im stumped. Maybe the plugs are fouled? Bad wires? Bad battery? What could be wrong???
 
So, they are high resistance injectors... I haven't really heard of too many people doing that in the first place. You may need to reset your ecu.

What do your datalogs look like?

One other thing to mention. I use 1000cc injectors and was going to do a smog test and put the stock ones back in and cause the ecu to engage the als and the car didn't run right. So, I went and swapped the 1000cc injectors back in and it went back to normal.

Try this out and see what happens.
 
Maybe the plugs are fouled? Bad wires? Bad battery? What could be wrong???


It is really easy to pull the plugs and check them. I doubt it is the wires.

Since the EPROM ECU "learns" you may have saved some bad settings that need to be cleared.

Did you slap some larger injectors into your car and not compensate for them or check to see the procedure for using high resistance injectors in a DSM?
 
It is really easy to pull the plugs and check them. I doubt it is the wires.

Since the EPROM ECU "learns" you may have saved some bad settings that need to be cleared.

Did you slap some larger injectors into your car and not compensate for them or check to see the procedure for using high resistance injectors in a DSM?


The stock ECU is in now, not the eprom. I installed the 750s when I had the eprom/ dsmlink, so yes I was compensating for them. No I didnt realise/ think to check...my brother got them for me for my birthday, and he didnt realise either.

Im really confused. If I go to start it in the morning with a fresh start, it takes a lot of cranks to get it started. But once it starts, and if I turn the car off, then back on again, it only takes the normal amount of cranks/ a lot less cranks to start the car. What would cause this???:cry:

BTW, the car runs just fine. It just takes a while to start.
 
You need to make the electrical system able to drive high resistance injectors, that is your problem. Or get injectors that the ECU can handle.
 
You need to make the electrical system able to drive high resistance injectors, that is your problem. Or get injectors that the ECU can handle.

The stock injectors are in, not the 750s and the car still takes a while to start. It cranks and cranks and cranks and cranks then finally starts. This all started after I installed the 750s.
 
the tip of the plugs are black and dry. they were white, indicating a lean condition, but thats when the 750s were in and we were trying to tune....I couldnt keep the car at WOT for more than a second or two after boost kicked in because the a/f ratio's would rocket to the 13s, and sometimes 14s immedietely.
 
I am guessing you got your a/f reading from dsmlink. Try datalogged both from my aem uego and my dsmlink and the link wasn't set right, in result the ratios were way off.

Black plug indicate a really rich condition. How much carbon build up did it have? Was it caked on there or just a little bit. I know getting the carbon to build up really thick takes time but, you never know.

Did you try to adjust the fuel for where it was leaning out?

I know you need a special resister to run high resistance injectors for them to run right.


You said your plug were black and dry then, when did they become white?

There maybe a completely different problem that you haven't discovered yet.


Edit: I just realized you have an aem uego. Did you manage to hook it up to the ecu so you could datalog it?
 
if you have an aftermarket fuel pressure regulator it is normal for the car to take a couple of extra cranks to start. The reason why the car wasnt running right with the 750's is because they are high resistance, keep the stock injectors in and reinstall your eprom ecu and set the adjustments to the stock injectors and you should be fine unless you did fry your eprom chip.
 
If I plug in the eprom, the car tries to start...it burps and backfires a lot. If I plug on the stock ecu, it runs fine. So im thinking the eprom is done.

NOW FOR ANOTHER PROBLEM
I just installed a new battery *I dont know if it has anything to do with this* and now Im hearing a tapping noise from somewhere around the battery...
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Im ready to throw someone through the wall. I just want my old car back :cry:
 
The higher resistance injectors are staying open to long(pulse width)
When you try to start the car in the morning after it cranks once push the throttle to the floor.That will shut the injectors off.It should fire rite up.
 
I had similar problems when I installed dsmlink & upgraded injectors - tough start, lots of burping/backfiring... and when I plugged stock ECU in, she started up fine. I didn't swap my wires correctly (dsmlinkwiki had posted the diagram incorrectly - but they fixed it now). Since my wires weren't swapped, she wasn't firing correctly, so oil seeped into my spark plug chamber (PIA to clean/seal).
Wondering if you're having the same problem.

What's your fuel pressure set at? Can you post a clip of your crank/start?
 
I had 750's installed in my 90 awd tsi this past may and my turbo guy had to "scale" them with my re-chipped ecu and dsmlink. I still have the stock fuel pump and fpr. Car runs good, but rich. I haven't fine-tuned it yet.

Also, I had Rod Knock last year and spun all my bearings. That sounds like rod-knock but when I accelerated the knock could still be heard during acceleration.
 
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