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View Full Version : New ZR1 owner-timing & sparkplug question


90_ZR1
11-01-2016, 08:41 PM
I just got my first ZR-1 (1990) last week and drove it for the first time this evening.
It doesn't idle too badly, but misfires badly when driving. My first question is what sparkplugs are recommended. I pulled one plug and it's an AC Delco 41-800. I saw another post where someone had 41-620's.
I would also like to know if the timing is adjustable, and what it should be if so.
Any advice appreciated.

XfireZ51
11-01-2016, 09:30 PM
I just got my first ZR-1 (1990) last week and drove it for the first time this evening.
It doesn't idle too badly, but misfires badly when driving. My first question is what sparkplugs are recommended. I pulled one plug and it's an AC Delco 41-800. I saw another post where someone had 41-620's.
I would also like to know if the timing is adjustable, and what it should be if so.
Any advice appreciated.

Timing change needs to be done by modifying the calibration.

90_ZR1
11-01-2016, 09:34 PM
Ok. Is that something which you can explain?

PhillipsLT5
11-01-2016, 09:34 PM
Probably injectors problem


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zrfast1
11-01-2016, 10:16 PM
Ok. Is that something which you can explain?

You need special tooling and expertise to interface your computer chip (prom) which is your ECM brain. Hope that helps

We Gone
11-01-2016, 10:19 PM
Welcome, most all your questions can be answered here.

http://www.zr1.net/forum/showthread.php?t=16778

look at post 3, coils and plugs

90_ZR1
11-02-2016, 09:31 PM
Thanks for the input guys!

XfireZ51
11-02-2016, 10:11 PM
Ok. Is that something which you can explain?

Timing is likely not ur issue.

henryr
11-03-2016, 08:59 AM
mine has a slight and / or occasional miss 2-3k....

not sure if the car has the stock injectors or not at 26k miles

going to order a set of new injectors as the plugs look okay

PhillipsLT5
11-03-2016, 06:52 PM
http://www.zr1specialist.com/HAT%20Web/articles/Measuring%20Fuel%20Injector%20Resistance%20with%20 the%20Plenum%20in%20Place.pdf

90_ZR1
11-12-2016, 11:20 PM
That file is very detailed and helpful. Very technical, but I should be able to figure it out.