1991 civic mystery

[ITC007]

I hope someone may know what this problem is..

I have a 1991 civic ITC race car.

At rpms around 3500 to 5500 I (seems to be) lose a cylinder, not sure which cylinder! I have done all the obvious including checking the valve lash, which I had adjusted. I have put in an MSD ignition, changed the spark plugs several times, checked ohms on plug wires, rebuilt the whole distributer and changed computers.
I'm getting nowhere with the car and it only seems to get worse. Any help with this gremlin would be appreciated.
Thanks in advance.

Devin
ITC#12

[MadFrog]

Originally posted by ITC007@Aug 8 2005, 04:22 PM
I hope someone may know what this problem is..

I have a 1991 civic ITC race car.

At rpms around 3500 to 5500 I (seems to be) lose a cylinder, not sure which cylinder! I have done all the obvious including checking the valve lash, which I had adjusted. I have put in an MSD ignition, changed the spark plugs several times, checked ohms on plug wires, rebuilt the whole distributer and changed computers.
I'm getting nowhere with the car and it only seems to get worse. Any help with this gremlin would be appreciated.
Thanks in advance.

Devin
ITC#12

[snapback]58002[/snapback]

here are a couple of other "obvious" things to check:
- double check all your grounds. Maybe you only have a marginal one somewhere.
- check the rev limit setting on the MSD?
- check the battery/alternator
- injector connections
- injectors themselves
- fuel filter

just a few things off the top of my head based on your description/guesses.

hth.

[zracre]

also check valve lash (not too tight) and get a good fuel pressure guage so you can see what pressure you are having when it is failing...

[tac911t]

Was this problem happening durning the race at Mid-Ohio this past weekend?
If it was, you would have gotten around the yellow CRX and stayed there.

P.S. It was me that pointed both of you by, for the two of you to finish your race without. You had a good race with him, both behind and in-front of me.

[spnkzss]

Originally posted by ITC007@Aug 8 2005, 04:22 PM
- double check all your grounds. Maybe you only have a marginal one somewhere.

[snapback]58002[/snapback]

That is a big one. I gave up on that stupid ground that jumps from the body to the motor. I installed a 1" wide ground strap. No more worries about stupid ground issues.

[ITC007]

Originally posted by tac911t@Aug 9 2005, 05:00 PM
Was this problem happening durning the race at Mid-Ohio this past weekend?
If it was, you would have gotten around the yellow CRX and stayed there.

P.S. It was me that pointed both of you by, for the two of you to finish your race without. You had a good race with him, both behind and in-front of me.

[snapback]58090[/snapback]

Yes that was me. Yes that problem was really bad during Sunday race, and one of the reasons I could not get around right away. I watched the video and I saw that I lost about 2 seconds during the end of the straight. This would happen 2-3 times a lap coming on to the front stretch, the back stretch and through thunder valley. It did however get a little better during the last few laps.
Bill and I had a great racewith and without you at the end. It was by far the most exciting race I have raced so far. Great fun too.

I have put new grounds from the motor to the headlight area, but I will try to put a much better strap in. Good advice. Has this happened to you?

I had the valve lash adjusted and thought this might cure the problem. It didnt. I have put in a pressure gauge for the fuel and the fuel always has good pressure.

Devin

[Guest_USGUYS_*]

Make sure that you have a ground to the cylinder head. That annoying small wire from the value cover to raditor support is critical. Find an open tapped boss on the head and put a battery cable sized wire from it to the chassis.

[H5Civic]

Be sure and double check the distributor is working properly. Mark Connolly and has been having a problem w/ this since the 1st of May in his ITC Civic that he holds the track record at Nelson Ledges with, and I've had the problem for going on 2 years. Last night Mark was finally able to work on the car and after 3 hours of checking every sensor on the car, he changed distributors, and the problem went away.

For us, the problem wouldn't allow us to hold the throttle flat on the floor, so we had to hold it at 3/4 throttle for the car to accelerate at all. Evidently there are 2 sensors inside the dizzy, one that sends a signal for spark, the other sends a signal for the injectors to fire. If one or both of these sensors go bad, then you are getting the injectors not spraying at the same time as when the spark is needed, thus the hiccup and no acceleration.

I've tried 2 other dizzy's in the past 2 years, but both were from junk yard cars. I seriously doubt that you'd notice this problem on a street car because you wouldn't spend much time at WOT, whereas we spend ALL the time at WOT. I'll be changing my dizzy tonight and am racing at Waterford Hills this coming weekend, so I'll let you know how things work.

Just my $.02.

[ITC007]

Originally posted by H5Civic@Aug 10 2005, 05:04 PM
Be sure and double check the distributor is working properly. Mark Connolly and has been having a problem w/ this since the 1st of May in his ITC Civic that he holds the track record at Nelson Ledges with, and I've had the problem for going on 2 years. Last night Mark was finally able to work on the car and after 3 hours of checking every sensor on the car, he changed distributors, and the problem went away.

For us, the problem wouldn't allow us to hold the throttle flat on the floor, so we had to hold it at 3/4 throttle for the car to accelerate at all. Evidently there are 2 sensors inside the dizzy, one that sends a signal for spark, the other sends a signal for the injectors to fire. If one or both of these sensors go bad, then you are getting the injectors not spraying at the same time as when the spark is needed, thus the hiccup and no acceleration.

I've tried 2 other dizzy's in the past 2 years, but both were from junk yard cars. I seriously doubt that you'd notice this problem on a street car because you wouldn't spend much time at WOT, whereas we spend ALL the time at WOT. I'll be changing my dizzy tonight and am racing at Waterford Hills this coming weekend, so I'll let you know how things work.

Just my $.02.

[snapback]58176[/snapback]

Thank you,

I didnt know that, I hope you fix your problem, and good luck at Waterford!!
I also have tried other dizzy's and I thought it was something else because it still had a similar problem. I will look into that and please let me know your outcome.

Devin

[ITC007]

H5 civic,

How did the weekend go for you at waterford? I hope you had a good time!
It is a fun track to race at. I hope you figuured out your problem. BTW, I got a new dizzy and will be installing it this week.

Devin

[joeg]

So Mark finally repaired the "U-Boat" issue?

[ITC007]

:119:

[H5Civic]

Originally posted by ITC007@Aug 15 2005, 12:50 PM
H5 civic,

How did the weekend go for you at waterford? I hope you had a good time!
It is a fun track to race at. I hope you figuured out your problem. BTW, I got a new dizzy and will be installing it this week.

Devin

[snapback]58393[/snapback]

Devin,

Unfortunately, my new 4.73FD gave me fits all last week and I wasn't able to take the car to Waterford. I'm finishing up putting the car back together right now, and will be doing an auto-x this coming Sunday. I'll let you know how things go w/ that.

Sam

[ITC007]

Sam,

Good luck with that. I heard on the Waterford Hills forum that everyone had a blast and enjoyed the nasa group being out there. The nasa guys also liked the track and our group adn want to try to do it again next year.

Devin

[charrbq]

Originally posted by ITC007@Aug 8 2005, 08:22 PM
I hope someone may know what this problem is..

I have a 1991 civic ITC race car.

At rpms around 3500 to 5500 I (seems to be) lose a cylinder, not sure which cylinder! I have done all the obvious including checking the valve lash, which I had adjusted. I have put in an MSD ignition, changed the spark plugs several times, checked ohms on plug wires, rebuilt the whole distributer and changed computers.
I'm getting nowhere with the car and it only seems to get worse. Any help with this gremlin would be appreciated.
Thanks in advance.

Devin
ITC#12

[snapback]58002[/snapback]

I had a similar problem that turned out to be the alternator not charging completely. Car ran great, but as the race progressed, it went to crap. Cut out like crazy at load in fourth. One thing I hadn't considered about my mysterious cut out on acceleration below 5G was the ground strap to the chassis. Thanks guys, I'll replace that one and see if it works. I knew there was a reason I watched this site besides the bench racing.