1991 ZR1 ODB1 Port Location - Page 3 - ZR-1 Net Registry Forums

roadczar · 04-05-2014

The plan for today is to replace the spark plugs and recheck for vacuum leaks...

Looked at couple of the plugs. The first looked OK, but the second looked pretty sooty. The spark looked strong. Injectors seem like a likely culprit.

roadczar · 04-05-2014

Forgot to mention - Last owner had a Doug Rippee Performance chip installed. I'm not familiar with that tuner. I wonder if it would be worthwhile to go back to the stock chip that came with the purchase....?

XfireZ51 · 04-05-2014

Some of the sootiness may be due to the issues you described when you first got the car. I would get new plugs and take a look after a few drives. If you can do a scan, see where the BLMs are.

roadczar · 04-05-2014

Quote:

Originally Posted by XfireZ51

Some of the sootiness may be due to the issues you described when you first got the car. I would get new plugs and take a look after a few drives. If you can do a scan, see where the BLMs are.

What does BLM stand for?

XfireZ51 · 04-05-2014

Quote:

Originally Posted by roadczar

What does BLM stand for?

Block Learn Multiplier. It is active in Closed Loop. At 128, it means the ECM is making no change to the base fuel map. So a scantool will tell you if you're running rich or lean and where.

roadczar · 04-05-2014

No luck after replacing the plugs
Did the paper clip diagnostic:
http://youtu.be/tl7aOi9GetY

From what I could tell:
31 - Cam Sensor Missing or Too Many Pulses
33 - MAP Sensor Voltage High
44 - Oxygen Sensor (Left Bank Lean)
55 - Fuel Monitor Lean
64 - Right Oxygen Sensor (Right Bank Lean)
66 - ??

Looks like a mess?

XfireZ51 · 04-05-2014

Quote:

Originally Posted by roadczar

No luck after replacing the plugs
Did the paper clip diagnostic:
http://youtu.be/tl7aOi9GetY

From what I could tell:
31 - Cam Sensor Missing or Too Many Pulses
33 - MAP Sensor Voltage High
44 - Oxygen Sensor (Left Bank Lean)
55 - Fuel Monitor Lean
64 - Right Oxygen Sensor (Right Bank Lean)
66 - ??

Looks like a mess?

When you have multiple MALF codes like this, first place to look is making sure the memcal is seated properly. Also, disconnect the BATT and erase. These may all be in history. Make sure to see if they come back, ie CEL again.
Also, make certain the ECM ground is in good shape. I hope you have an FSM.

roadczar · 04-05-2014

I did reseat the chip. Disconnected the battery, then went for a 50 mile drive. No codes, but still running like crap.

What is the part number of manual? I do have a ZR1 supplement.

Went for another drive and it threw 55. Fuel pressure?

mike100 · 04-05-2014

I would say to ohm out the injector harness. There's a link to the how-to somewhere- It will take about an hour, but you can meter out the injector resistance to find the worst injectors. If you even have one bad one, plan on doing that for sure. It sounds like one other thing might be wrong as well.

One bad O2 sensor on one bank will also cause issues...it would save a ton of time if you can meet up with somebody with a laptop program or the factory tech1 scanner to look at operating parameters real-time when the engine is running- not just reading code history.

XfireZ51 · 04-06-2014

Quote:

Originally Posted by roadczar

I did reseat the chip. Disconnected the battery, then went for a 50 mile drive. No codes, but still running like crap.

What is the part number of manual? I do have a ZR1 supplement.

Went for another drive and it threw 55. Fuel pressure?

Fuel pump(s)?. At least the other codes didn't come back.

04-05-2014	#21
roadczar Join Date: Mar 2014 Location: Chicagoland Posts: 23	Re: 1991 ZR1 ODB1 Port Location The plan for today is to replace the spark plugs and recheck for vacuum leaks... Looked at couple of the plugs. The first looked OK, but the second looked pretty sooty. The spark looked strong. Injectors seem like a likely culprit.

04-05-2014	#22
roadczar Join Date: Mar 2014 Location: Chicagoland Posts: 23	Re: 1991 ZR1 ODB1 Port Location Forgot to mention - Last owner had a Doug Rippee Performance chip installed. I'm not familiar with that tuner. I wonder if it would be worthwhile to go back to the stock chip that came with the purchase....?

04-05-2014	#23
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,683	Re: 1991 ZR1 ODB1 Port Location Some of the sootiness may be due to the issues you described when you first got the car. I would get new plugs and take a look after a few drives. If you can do a scan, see where the BLMs are.

04-05-2014	#26
roadczar Join Date: Mar 2014 Location: Chicagoland Posts: 23	Re: 1991 ZR1 ODB1 Port Location No luck after replacing the plugs Did the paper clip diagnostic: http://youtu.be/tl7aOi9GetY From what I could tell: 31 - Cam Sensor Missing or Too Many Pulses 33 - MAP Sensor Voltage High 44 - Oxygen Sensor (Left Bank Lean) 55 - Fuel Monitor Lean 64 - Right Oxygen Sensor (Right Bank Lean) 66 - ?? Looks like a mess?

04-05-2014	#28
roadczar Join Date: Mar 2014 Location: Chicagoland Posts: 23	Re: 1991 ZR1 ODB1 Port Location I did reseat the chip. Disconnected the battery, then went for a 50 mile drive. No codes, but still running like crap. What is the part number of manual? I do have a ZR1 supplement. Went for another drive and it threw 55. Fuel pressure? Last edited by roadczar; 04-05-2014 at 09:44 PM.

04-05-2014	#29
mike100 Join Date: Feb 2011 Location: San Marcos CA Posts: 1,786	Re: 1991 ZR1 ODB1 Port Location I would say to ohm out the injector harness. There's a link to the how-to somewhere- It will take about an hour, but you can meter out the injector resistance to find the worst injectors. If you even have one bad one, plan on doing that for sure. It sounds like one other thing might be wrong as well. One bad O2 sensor on one bank will also cause issues...it would save a ton of time if you can meet up with somebody with a laptop program or the factory tech1 scanner to look at operating parameters real-time when the engine is running- not just reading code history.