'91 missing and would like a second opinnion - Page 3 - ZR-1 Net Registry Forums

kenthompson · 02-24-2010

But would that make the car have no power without turning on a service light?

The car runs like the secondaries aren't working, but I've confirmed that the actuators are indeed working.

That's why I keep thinking fuel to the secondaires (or all of them not firing), or ignition timing.

Mikko, I did notice last night that each time you fire the care, you get a knock. Maybe the knock sensor is getting flakey and retarding the timing?

KT

Pete · 02-25-2010

If it's not fuel.
Can i ask what spark plugs are you using and where did you gap them/

Pete

ZR-1Mikko · 02-25-2010

It has brand new stock Ac delco plugs which I believe had the correct gap right out of the box...

Pete · 02-25-2010

I never seen a/c delcos gapped from the factory.

Can you take a couple out and check the gap,easy and free

Pete

ZR-1Mikko · 02-28-2010

If it is a failing O2 sensor would it be possible that it wouldn't show any codes for it?

Locobob · 02-28-2010

Quote:

Originally Posted by ZR-1Mikko

If it is a failing O2 sensor would it be possible that it wouldn't show any codes for it?

Yes, at least to some degree. I've noticed a lot on these cars can go wrong without tripping a code.

A26B · 02-28-2010

Quote:

Originally Posted by ZR-1Mikko

If it is a failing O2 sensor would it be possible that it wouldn't show any codes for it?

One way to check is to drive with rpm higher than 3200 rpm, i.e. in open loop. If the miss disappears, it's likely the O2's. If an O2 fails, it will throw a code (or supposed to anyway) & will run like crap in closed loop.

I had water get into the RH O2 connector on a trip from Houston to OKC. Engine was about to shake out of the Zee until I got it into open loop. Drove it the last 150 miles just into open loop & made it home fine.

ZR-1Mikko · 02-28-2010

It definitely has a miss after 3200 rpm's. It must be a sensor of somekind. I think I just need to find connector to plug a computer to it...

LT5-Lee · 02-28-2010

In a regular situation on a common GM car, a knock sensor would be a logical choice after going through all the variables you exhausted.

I had such a problem a while back and traced it to a MAP sensor plug that looked and felt plugged in, but was not. It was so close it worked until the engines torque movement or rapid acceleration must have caused a disconnect on one terminal. From now on, I do not consider it connected until you hear a loud click when connecting it. It is a pain, but disconnecting & reconnecting all the terminals you can get too might pay off and make sure your grounds are in good shape. I plan on adding a few in the future just for grins.

A26B · 02-28-2010

Quote:

Originally Posted by ZR-1Mikko

It definitely has a miss after 3200 rpm's. It must be a sensor of somekind. I think I just need to find connector to plug a computer to it...

I think you have eliminated the O2 sensors.

As for the knock sensor, a bad sensor or lead will give you a SES light and prevent secondary operation.

I haven't read the whole thread, have you pulled codes, cleared and restablished codes?

02-24-2010	#21
kenthompson Join Date: Jul 2007 Location: Las Vegas Posts: 298	Re: '91 missing and would like a second opinnion But would that make the car have no power without turning on a service light? The car runs like the secondaries aren't working, but I've confirmed that the actuators are indeed working. That's why I keep thinking fuel to the secondaires (or all of them not firing), or ignition timing. Mikko, I did notice last night that each time you fire the care, you get a knock. Maybe the knock sensor is getting flakey and retarding the timing? KT __________________ 1990 Grey/Black Too many for the sig.

02-25-2010	#22
Pete Join Date: Dec 2003 Location: Chicagoland,IL Posts: 2,680	Re: '91 missing and would like a second opinnion If it's not fuel. Can i ask what spark plugs are you using and where did you gap them/ Pete __________________ '91 #1635 PoloGreen 350 LT5 11.09 @ 129.27 11.04 @ 128.86 474RWHP 400RWTQ http://www.youtube.com/watch?v=SFNFOhGGlR4 http://www.youtube.com/watch?v=ZlRIOMwaDYY https://sites.google.com/site/peteszr1garage

02-25-2010	#23
ZR-1Mikko Join Date: Dec 2005 Location: Las Vegas Posts: 108	Re: '91 missing and would like a second opinnion It has brand new stock Ac delco plugs which I believe had the correct gap right out of the box... __________________ If you don't put the miles on it, someone else will...

02-25-2010	#24
Pete Join Date: Dec 2003 Location: Chicagoland,IL Posts: 2,680	Re: '91 missing and would like a second opinnion I never seen a/c delcos gapped from the factory. Can you take a couple out and check the gap,easy and free Pete __________________ '91 #1635 PoloGreen 350 LT5 11.09 @ 129.27 11.04 @ 128.86 474RWHP 400RWTQ http://www.youtube.com/watch?v=SFNFOhGGlR4 http://www.youtube.com/watch?v=ZlRIOMwaDYY https://sites.google.com/site/peteszr1garage

02-28-2010	#25
ZR-1Mikko Join Date: Dec 2005 Location: Las Vegas Posts: 108	Re: '91 missing and would like a second opinnion If it is a failing O2 sensor would it be possible that it wouldn't show any codes for it? __________________ If you don't put the miles on it, someone else will...

02-28-2010	#29
LT5-Lee Join Date: Jan 2009 Location: Houston, Tx. Posts: 59	Re: '91 missing and would like a second opinnion In a regular situation on a common GM car, a knock sensor would be a logical choice after going through all the variables you exhausted. I had such a problem a while back and traced it to a MAP sensor plug that looked and felt plugged in, but was not. It was so close it worked until the engines torque movement or rapid acceleration must have caused a disconnect on one terminal. From now on, I do not consider it connected until you hear a loud click when connecting it. It is a pain, but disconnecting & reconnecting all the terminals you can get too might pay off and make sure your grounds are in good shape. I plan on adding a few in the future just for grins. __________________ An Unarmed Citizen is a Future Peasant. Something BLOWbama & Hilary are trying to accomplish now at the UN with the "Global Small Arms Treaty"