Sick '90 LT5 - ZR-1 Net Registry Forums

N8nSM · 02-22-2006

Hey all, newbie to the ZR-1 Net registry. I've been over on CorvetteForum.com a bit and posed this same question to them. I thought I'd throw it out here and see what I get back.

I went playing with the Z a few weeks back and was showing off a bit for my Uncle who used to own a Lotus way back in the day. I drove it back to my Mom's house and went inside for a little bit. When I went back out to the car it started fine. I got about a block and a half and it started sputtering real hard when it was in gear and loosing power. It picked back up at idle when I pushed the clutch in but would die off as soon as tried to getback in gear. I walked back to my Mom's house and then went back later that evening. It started and I got it home only a few blocks away. Shortly after I pulled in the driveway it died again. It would start but when I tried to put it in gear it would die off.

I let it sit for a couple weeks. Been busy with work yadda yadda yadda. I came back to find a dead battery, jump started it and it ran fine for a bit and then died. I've repeated this a couple times and keep getting the same thing. It seems to run fine in open loop but when it switches to closed it dies off.

Where should I start? I've got a new Optima yellow top going in anyway, although I don't think the battery has anything to do with it.

Thanks,

-Nate

02-22-2006

Check primary fuel pump.

Check fuel pressure with key on.

Check fuel pressure while running with primary fuel pump fuse pulled. Car should die once it reaches 176 degrees on the coolant.

Let car cool down 30 minutes. Insert primary fuel pump fuse, pull secondary fuse. Start car, note how car runs only on primary.

Z Factor · 02-22-2006

Hello Nate and welcome to the forum.

Jeff has given you some good advice.

I would say that since many have responded to your thread in the other forum they will not be redundant and repeat it here. However, others who don't visit or care for that other place will be glad to give advice.

Bell Curve · 02-23-2006

Sounds like either injectors, pump, filter or all three. Could also be the chip

tomtom72 · 02-23-2006

The simple things first: Using the Helm manual flow chart for the fuel pressure test, section 6E = Driveability & Emissions, if you follow the chart you will know that both pumps are good or which is bad. If the pumps pass muster, I would scan the motor running in open and closed loop. The block learn numbers and the O2 readings will tell you which way to go if the injectors are bad, or it may turn up something else. The scan will also let you see any codes, present or history, which could aid in diagnosing the problem.

Nothing much can be said before you have some data and have run some tests. The general direction of bad fuel filter, pumps, injectors trouble, plugs, wires, coils, gets refined after following the Helms manual flow charts for trouble shooting.

I'm only saying this because it is better to follow the manual diagnostic charts than guess. The senoir guys like Jeffvette and Bell Curve gave you the most likely suspects, now you have to do your diagnostics starting with those systems.

Tom

N8nSM · 02-26-2006

Just an update and a thanks. I found it was the primary fuel pump. The motor had heated up and actually melted the plastic around it. I noticed it was blowing the fuel pump fuse so I went ahead and pulled it from the tank. Sure enough, melted. I also found that my Fuel Pressure Regulator was leaking. Both parts on order and hopefully I'll be putting it back together on Tuesday...

Thanks again for the great advice. Much appreciated.

-Nate

02-22-2006	#1
N8nSM Join Date: Feb 2006 Location: Santa Maria, CA Posts: 20	Sick '90 LT5 Hey all, newbie to the ZR-1 Net registry. I've been over on CorvetteForum.com a bit and posed this same question to them. I thought I'd throw it out here and see what I get back. I went playing with the Z a few weeks back and was showing off a bit for my Uncle who used to own a Lotus way back in the day. I drove it back to my Mom's house and went inside for a little bit. When I went back out to the car it started fine. I got about a block and a half and it started sputtering real hard when it was in gear and loosing power. It picked back up at idle when I pushed the clutch in but would die off as soon as tried to getback in gear. I walked back to my Mom's house and then went back later that evening. It started and I got it home only a few blocks away. Shortly after I pulled in the driveway it died again. It would start but when I tried to put it in gear it would die off. I let it sit for a couple weeks. Been busy with work yadda yadda yadda. I came back to find a dead battery, jump started it and it ran fine for a bit and then died. I've repeated this a couple times and keep getting the same thing. It seems to run fine in open loop but when it switches to closed it dies off. Where should I start? I've got a new Optima yellow top going in anyway, although I don't think the battery has anything to do with it. Thanks, -Nate __________________ [FONT=Tahoma][COLOR=blue][B]Nate[/B][/COLOR][/FONT] [FONT=Tahoma][COLOR=blue][B]Santa Maria, CA[/B][/COLOR][/FONT] [FONT=Tahoma][COLOR=blue][B]1990 ZR-1 #224[/B][/COLOR][/FONT]

02-22-2006	#2
Jeffvette Guest Posts: n/a	Re: Sick '90 LT5 Check primary fuel pump. Check fuel pressure with key on. Check fuel pressure while running with primary fuel pump fuse pulled. Car should die once it reaches 176 degrees on the coolant. Let car cool down 30 minutes. Insert primary fuel pump fuse, pull secondary fuse. Start car, note how car runs only on primary. Last edited by Jeffvette; 02-22-2006 at 05:57 PM.

02-22-2006	#3
Z Factor Join Date: Dec 2003 Location: S. Florida Posts: 2,667	Re: Sick '90 LT5 Hello Nate and welcome to the forum. Jeff has given you some good advice. I would say that since many have responded to your thread in the other forum they will not be redundant and repeat it here. However, others who don't visit or care for that other place will be glad to give advice.

02-23-2006	#4
Bell Curve Join Date: Aug 2005 Location: Pineridge Posts: 341	Re: Sick '90 LT5 Sounds like either injectors, pump, filter or all three. Could also be the chip

02-23-2006	#5
tomtom72 Join Date: Dec 2004 Location: Jacksonville, FL USA Posts: 4,645	Re: Sick '90 LT5 The simple things first: Using the Helm manual flow chart for the fuel pressure test, section 6E = Driveability & Emissions, if you follow the chart you will know that both pumps are good or which is bad. If the pumps pass muster, I would scan the motor running in open and closed loop. The block learn numbers and the O2 readings will tell you which way to go if the injectors are bad, or it may turn up something else. The scan will also let you see any codes, present or history, which could aid in diagnosing the problem. Nothing much can be said before you have some data and have run some tests. The general direction of bad fuel filter, pumps, injectors trouble, plugs, wires, coils, gets refined after following the Helms manual flow charts for trouble shooting. I'm only saying this because it is better to follow the manual diagnostic charts than guess. The senoir guys like Jeffvette and Bell Curve gave you the most likely suspects, now you have to do your diagnostics starting with those systems. Tom __________________ 1990 ZR-1, Black/grey, #2233, stock. ZR-1 Net Reg Founding Member #316 & NCM member

02-26-2006	#6
N8nSM Join Date: Feb 2006 Location: Santa Maria, CA Posts: 20	Re: Sick '90 LT5 Just an update and a thanks. I found it was the primary fuel pump. The motor had heated up and actually melted the plastic around it. I noticed it was blowing the fuel pump fuse so I went ahead and pulled it from the tank. Sure enough, melted. I also found that my Fuel Pressure Regulator was leaking. Both parts on order and hopefully I'll be putting it back together on Tuesday... Thanks again for the great advice. Much appreciated. -Nate __________________ [FONT=Tahoma][COLOR=blue][B]Nate[/B][/COLOR][/FONT] [FONT=Tahoma][COLOR=blue][B]Santa Maria, CA[/B][/COLOR][/FONT] [FONT=Tahoma][COLOR=blue][B]1990 ZR-1 #224[/B][/COLOR][/FONT]