still the same old problem! - ZR-1 Net Registry Forums

Harold Broerman · 10-25-2008

HI Guys, I havent driven my 90 zr1 for a while, and i thought i had this code 61 problem solved. it seems not, after following all members tips, and replacing both fuel pumps, o2 sensors, vacumn switch in the intake valley, checking all vacumn connections for leaks, and lastly sending the ecu out for rebuild., i drove the car a few times, and it seemed fine, but yesterday, after driving just a few miles, the ses lite came on and the car wont go past 3000 rpm. i let the car sit a couple hours, started it up, and same thing again. runs a few miles perfect, then the ses lite comes on , and car wont accelerate again.i checked with a code scan tool and it says code 61. this is driving me nuts! any help would be greatly appreaciated.thanks, Harold. ps, this is a 10,000 mile car.800-475-5431 days 6am-2pm pacific time.

XfireZ51 · 10-25-2008

Harold,

Code 61 is Port Throttle System failure that is set when ECM "sees" the secondary MAP sensor voltage dropping below .6v. That means there isn't enough vacuum to keep the secondaries throttle plates open.
Some questions:
1. Is the secondary vacuum pump operational? Does it turn on with ignition ON?

2. Have you datalogged motor as it runs through the point where it sets SES light?

3. Have you checked to see if vacuum holds when motor is shutdown?

4. Have you tried replacing secondary MAP sensor and checked harness connector?

rhipsher · 10-25-2008

If it throws and ses light under hard acceleration then there's three things you need to check that you havn't listed. 1st there are two check valves under the plenum you need to check. You should be able to put it up to you mouth and blow air through them in one direction. #2 There is a secondary vacume solenoid that can go bad. #3 both vacume actuators need to hold a vacume or your butterfly valves will never stay open. All these will cause a code 61 and your car will run out of breath at 4000rpm's. My problem was a secondary vacume solenoid. It costs only $39.00 bucks and my problem was solved.

tomtom72 · 10-26-2008

Jez Harold this is turning into a real ball breaker!

The code erases itself upon restart.... it sets if you are getting into the secondaries, right?

It also sets if you are not into the secondaries?....do I read you correctly?

This stinks of an electrical gremlin if all the mechanical parts of the system pass muster like the guys are saying.

I intend no insult, you did run thru the diagnostic charts in the Helm FSM ? I know when I had my 61 it was a bit tough to do those charts as I didn't have a Tech1A and I had to use the alternate chart to use a DVOM and it was tedious at best for me. The one thing that I noticed using my snap-on scanner during my 61 episode was that when I used the "clear codes" option with the car at idle, the code would reset in a split second....which kind of made me think an electrical issue being at fault. I mean unless I had a leak in the sys the size of the grand canyon....how would it reset so fast? I think that if I was smart I would have concentrated on the electrical aspects based on what the scanner was trying to tell me....turned out to be my ECM.

Who did your ECM? I couldn't find anyone that wanted to work on mine....all I kept hearing was L98...okay, ZR-1....we will give it a shot.

Tom

10-25-2008	#1
Harold Broerman Join Date: Jan 2007 Location: lancaster,ca. Posts: 17	still the same old problem! HI Guys, I havent driven my 90 zr1 for a while, and i thought i had this code 61 problem solved. it seems not, after following all members tips, and replacing both fuel pumps, o2 sensors, vacumn switch in the intake valley, checking all vacumn connections for leaks, and lastly sending the ecu out for rebuild., i drove the car a few times, and it seemed fine, but yesterday, after driving just a few miles, the ses lite came on and the car wont go past 3000 rpm. i let the car sit a couple hours, started it up, and same thing again. runs a few miles perfect, then the ses lite comes on , and car wont accelerate again.i checked with a code scan tool and it says code 61. this is driving me nuts! any help would be greatly appreaciated.thanks, Harold. ps, this is a 10,000 mile car.800-475-5431 days 6am-2pm pacific time.

10-26-2008	#4
tomtom72 Join Date: Dec 2004 Location: Jacksonville, FL USA Posts: 4,637	Re: still the same old problem! Jez Harold this is turning into a real ball breaker! The code erases itself upon restart.... it sets if you are getting into the secondaries, right? It also sets if you are not into the secondaries?....do I read you correctly? This stinks of an electrical gremlin if all the mechanical parts of the system pass muster like the guys are saying. I intend no insult, you did run thru the diagnostic charts in the Helm FSM ? I know when I had my 61 it was a bit tough to do those charts as I didn't have a Tech1A and I had to use the alternate chart to use a DVOM and it was tedious at best for me. The one thing that I noticed using my snap-on scanner during my 61 episode was that when I used the "clear codes" option with the car at idle, the code would reset in a split second....which kind of made me think an electrical issue being at fault. I mean unless I had a leak in the sys the size of the grand canyon....how would it reset so fast? I think that if I was smart I would have concentrated on the electrical aspects based on what the scanner was trying to tell me....turned out to be my ECM. Who did your ECM? I couldn't find anyone that wanted to work on mine....all I kept hearing was L98...okay, ZR-1....we will give it a shot. Tom __________________ 1990 ZR-1, Black/grey, #2233, stock. ZR-1 Net Reg Founding Member #316 & NCM member

10-25-2008	#2
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,706	Re: still the same old problem! Harold, Code 61 is Port Throttle System failure that is set when ECM "sees" the secondary MAP sensor voltage dropping below .6v. That means there isn't enough vacuum to keep the secondaries throttle plates open. Some questions: 1. Is the secondary vacuum pump operational? Does it turn on with ignition ON? 2. Have you datalogged motor as it runs through the point where it sets SES light? 3. Have you checked to see if vacuum holds when motor is shutdown? 4. Have you tried replacing secondary MAP sensor and checked harness connector?

10-25-2008	#3
rhipsher Join Date: Aug 2008 Location: Houston, TX Posts: 2,319	Re: still the same old problem! If it throws and ses light under hard acceleration then there's three things you need to check that you havn't listed. 1st there are two check valves under the plenum you need to check. You should be able to put it up to you mouth and blow air through them in one direction. #2 There is a secondary vacume solenoid that can go bad. #3 both vacume actuators need to hold a vacume or your butterfly valves will never stay open. All these will cause a code 61 and your car will run out of breath at 4000rpm's. My problem was a secondary vacume solenoid. It costs only $39.00 bucks and my problem was solved.