Getting Spark Retard. Bad Knock Sensor?
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Registered User
Joined: Feb 2000
Posts: 178
From: Toronto, Ontario, Canada
Getting Spark Retard. Bad Knock Sensor?
I went to the track last weekend and slapped a Scanmaster on my car. To my surprise I was getting a bunch of spark retard. (8-10 at times)
Driving home, even when I fluttered the throttle, driving at low RPM, it would register .1 to 1 degree..... and hammering it, the retard would fluctuate up top 8-10. Slowly however, it went away and I thought it may have been some bad gas.
No luck however as the retard has come back. The thing that really gets me is that it is so inconsistent, happening infrequently at every RPM and speed, and is usually started when I go WOT and continues even after when I'm crusiing..... however it doesn't happen all the time.
To figure out the problem, I have used different gas (92 and 94) and have also fixed that slight exhaust leak i was having. I checked the Fuel Pressure and everything seems good... my next step is to cap the cut-out, even though last year, I had no problems with the same mod.
I was thinking it may be a malfunctioning knock sensor (the knock module was replaced with the LT4). Is this common? Has anyone else had a similar problem?
Are there any other things I should look at before I start spending money? If it's not the module, what else could it be? I was thinking of flushing the injectors..... but I can't think of anything else.
Other than timing retard, I have no misses and the car drives very well..... I ran a 13.45 at 103 at the track even with the timing pulled.
Thanks in advance for the help guys.
Driving home, even when I fluttered the throttle, driving at low RPM, it would register .1 to 1 degree..... and hammering it, the retard would fluctuate up top 8-10. Slowly however, it went away and I thought it may have been some bad gas.
No luck however as the retard has come back. The thing that really gets me is that it is so inconsistent, happening infrequently at every RPM and speed, and is usually started when I go WOT and continues even after when I'm crusiing..... however it doesn't happen all the time.
To figure out the problem, I have used different gas (92 and 94) and have also fixed that slight exhaust leak i was having. I checked the Fuel Pressure and everything seems good... my next step is to cap the cut-out, even though last year, I had no problems with the same mod.
I was thinking it may be a malfunctioning knock sensor (the knock module was replaced with the LT4). Is this common? Has anyone else had a similar problem?
Are there any other things I should look at before I start spending money? If it's not the module, what else could it be? I was thinking of flushing the injectors..... but I can't think of anything else.
Other than timing retard, I have no misses and the car drives very well..... I ran a 13.45 at 103 at the track even with the timing pulled.
Thanks in advance for the help guys.
Registered User
Joined: Sep 2000
Posts: 491
From: Novi MI
I had a similar problem with my car. Sometimes the computer would pull sooo much timing the egine felt like it wanted to stop reving. Most of the time it would happen when I would throw the trans in a gear where the engine would be almosts topped out. EXAMPLE, say you drop it in second gear at 75mph and redline comes at 80mph so your already at 5000rpm when you try to accelerate. I had my computer tuned and the knock module desensatized and the problem went away.
Registered User
Joined: Dec 1999
Posts: 1,697
From: Petersham, MA
Try running some real good gas and see what happens. If you run 100 unleaded, and the knock goes away, you probably have a real detonation issue. If it doesn't go away, it's probably false knock.
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