1G N/T Problem... Needs fixed before Sunday

[Woita09]

Ok, I race my 91 Laser 2.0 N/T 5 speed at a dirt track. Overhauled the engine this winter (20 over pistons, BSEK, new lifters,oil pump, drilled the oil bypass on the filter housing, spark plugs, fuel filter,air filter, removed ps pump, ac compressor, EGR, evap, new clutch) made sure everything was hooked up correctly on install and precisely timed. It'll start right up every time but when I accelerate whether its in neutral or in gear it bogs out and sputters at about 3000 rpm and on the track occasionally I can get it up to about 5000... The conclusion I've made is the MAF. I could very well be wrong and so I decided to ask here. I'm pretty sure I have the only 1G dsm's In the whole county, so finding one off of a parts car isn't really an option to try. I don't know what else to check, I'm out of ideas!! The race is Sunday and I can order a new MAF and have it here later this week but I'd hate to spend that kind of cash and have a repeat of the last race (I was on my 5th/10 laps when the checkered flag dropped)
Thanks!

 

[Woita09]

It DOES seem like at a certain pedal position it cuts out, bout mid throttle, if you keep it below half throttle-ish it'll rev normal... Replaced the fuel pump this morning.. You can hear it a lot easier now

Tps checked out good, smooth climb...

 

[1gdsmnt58]

just throwing it out there but maybe tps or cam sensor? mine was doing sorta the same thing at one time an it wasn't putting out a CEL either but what mine was doing was between 2500-3000 rpms it would kinda rev up and down and kinda spit and sputter and i put in a new tps and it has been better ever since.

 

[JusMX141]

I'd rig something up to check fuel pressure- I'm thinking something's not right about the fuel supply. If it was a misfire the engine would still accelerate, just more slowly and with a noticeable "miss". With no check engine light, I'm not seeing how it could be anything outside of the fuel system.

 

[DSM1G90]

...plugged fuel filter.... ? Or, a pump getting tired on you..? I suspect the former to be the issue..
Need about 38lbs plus for the injectors.

As for the corrosion on the momboard: get some acetone to put on the momboard to scrub off the corrosion with a toothbrush.

Good luck - DSM

 

[Colt4G63 also]

Check the tps with a good graphing meter while you drive, it won't always show up during KOEO testing.

 

[horizontalkev]

Now that I think.about it, jusmx141 and DSM1G90 might just be right.. Try out your new fuel pump and if that doesn't change anything then check your fuel filter.. You checked your fuel pressure regulator correct?

 

[Woita09]

new fuel pump, new fuel filter, different injectors, pickup sock, tank was spotless. Ive crimped off the return line, jumped the fuel pump to constant power and still no change. The only things that i havent changed are- Ignitor, coil pack, TPS. Where its punched .020 over could the injectors be too small and not supplying enough fuel?

also I just called the mechanic that I took it to when I had enough. He said that he pulled off a vacuum line, injected fuel with a syringe and it hit redline when he revved it... so my other question is- What tells the injectors to fire, cas?

 

[Woita09]

drove 3 hours to pick up a coil pack and transistor, no change.

 

[tektic]

What ecu are you using. I had the same problem when using modified edm code in my ecu. My logs show the afr droping to below 18:1 above 60 tps around 3k rpm. I couldn't get my stock maf calabrated with that software no matter what I changed. I switched back to eb20 code with some maf running and no more problems. It can stand to be tuned better but as of right now I just don't have the time.

The short of it make sure your ecu and maf go together.
Edit: and your injector size.

 

[DSM1G90]

Where its punched .020 over could the injectors be too small and not supplying enough fuel

I would say you definitely got an A/F mixture issue here.

Stock injectors are the 240 variety.

What does the plugs looks like: soot black meaning running rich, or blistering white meaning your running lean?

Big issue is that a stock ECU is only going to work with stock injectors, thus, with enlarging the bore size, you could be running now on the lean side due to more vacuum draw. Maybe gradually increase the injector size if your plugs are blistering white since the stock fuel pump can easily push fuel through 450 injectors with no problem.

In the video, is the temp gauge correct? You running a 195 degree T-stat, or none, if none your sensors are having a hayday with the ECU giving false information and the ECU is pulling teeth trying to get everything in a closed loop operation..which could be your problem with performance.

 

[Sitro4g63]

Shoulda done a quote, sorry. No, it didn't sound like my problem. Car still no run good

Dsm troubles... - YouTube
^^^^^^^^^^^^^^^^^^^ Should be a video from this evening of what its doing.. Recorded off of my phone so its not the most steady video..

I happened to notice the temp gauge was all the way to high and your oil pressure gauge is not working? Oil is very important.low oil or pressure could cause friction in the cylinder chambers. Noise could be from pistons not running smoothly. Instead of sliding there skipping,.which also could cause retard ignition timing in the combustion chambers.

 

[Talon64]

Could it be leaking injector seals? Spray some starter fluid around and see if its revs up. I know my ICS o-ring had a slight tear and was causing me all kinds of issues

 

[Arthris]

This is a long shot but I had a similar ish issue that I remedied this week on my new motor. The issue I had was I put the crank alignment plate on back wards. The little plate that u use to align the crank when putting the timing belt on. Timing was perfect absolutely perfect but I had zero power above 3k and it would randomly missfire. Thought I had skipped a tooth but the plate was incorrect which put the cams way to advanced