1990 ZR1 problems

[Randall1]

Hello all, I have a 1990 ZR1 with 32k miles on it that has been in storage for about a year. I have started the car every month and wamed it up. The last time I tried starting the car it stumbled and backfired and the SES light stays on. The car did start and runs but not with the power it normally has. I checked the vacuum line in the back (hard to get to} and made sure it was tight. Checked the plugs and they look good and when I turn the key on I here the vacuum pump go on and then turn off like it should. I bought a fuel pressure gage today and a new fuel filter and will check pressure and change the filter tomorrow. I was just wondering if any of you folks have any ideas before I tear into the car. The engine intimidates me a little but I am pretty handy with a wrench.

Thanks,
Randall

[Jeffvette]

Randall, welcome to the group. More than likely you had a back fire from not holding the key over long enough while the engine was starting. You can take a flashlight and peek at the backside of the plenum and you will see the mao sensor. On the underneath side you will have an electrical connection and and a vacuum connection. The vacuum connection has more than likely come off at that point. Just reach under and reconnect.

BTW, check out our local group site www.pnwzr1.net

I also run a shop in Battle Ground and have a few guys that come down from the SeaTac area for service.

[Randall1]

Hello all, I have a 1990 ZR1 with 32k miles on it that has been in storage for about a year. I have started the car every month and wamed it up. The last time I tried starting the car, after many cranks it stumbled and backfired and the SES light stays on. The car did start and runs but not with the power it normally has. I checked the vacuum line in the back (hard to get to} and made sure it was tight. Checked the plugs and they look good and when I turn the key on I here the vacuum pump go on and then turn off like it should. I bought a fuel pressure gage today and a new fuel filter and will check pressure and change the filter tomorrow. I was just wondering if any of you before I tear into the car. The engine intimidates me a little but I am pretty handy with a wrench.

Thanks,folks have any ideas
Randall

[Randall1]

Thanks for the info. I did check the hose on the backside of the plenum and it does appear to be attached but will try to see if any cracks are in it using a mirror today. Last year it did come off and I re-attached it. The more I read the more I think the injectors may be a problem. I will check the fuel pressure and also buy a bottle of the injector cleaner (Redline I believe) and see if I can get it started and run it till warm.

Randall

[4DSZR1]

No problem running in northwest today Cold and sunny :)

[Sgreg]

If that gas has been in your tank for a year without a stabilizer, it may be contaminated with water. That will not help injectors. Just a thought.

[Randall1]

Ugh.......... it might be bad gas. No stabilizer for a year is not a good thing if the car has been sitting over a year. Live and learn I guess.

Randall

[Randall1]

Well, I spent a couple hours tracing all vacuum hoses looking for disconnections and found none. Should be getting my scout 2500 scanner in about 4 days so can pull the codes and see what is happening. The story gets better. After getting in my car and having it stumble and try to start I keep looking at the gas gauge making sure it has gas and it reads half full. I then decide the gas is bad and decide to drain and put new premium in. Total amount of gas to empty tank was about 3 quarts........EMPTY. I put 10 gallons of new gas in and tank reads full but at least I know I have enough gas and fresh. Try to start and stumbles coughs backfires and finally starts and after warm runs ok except SES light on and of course NO secondaries. The car does not want to start the next day but will if cranked for awile but I am not willing to risk burning the starter motor up so will continue my adventure. I did purchase a new fuel filter and will install today. Always open for suggestions.

Thanks,
Randall

[tccrab]

Dig out a paperclip and pull the codes.
We'll need to know what is triggering the SES code.
Remember, you only need three things for the car to start, fuel, air and spark.
It's getting air so that can be ruled out.
There's a fairly straightforward procedure to check the fuel pumps, and of course do change the fuel filter.
I doubt seriously that all your primary fuel injectors have gone south at once, but you never know......
And it would be very unusual to lose all 4 coil packs at once...
Bad O2 sensors will cause all kinds of fun stuff after the car goes into closed loop, but the engine should start correctly.

Pull the codes, work from there...

[Jeffvette]

Randall, I'll be up in Seattle this weekend for the swap meet. I'll be dropping off a ZR-1 for a customer as well. I am willing to come by and check it out for you.

[A26B]

Randall,
You should always try to keep the tank completely full, especially when it's sitting for long periods of time. Here's what happens when the fuel pump assy is exposed to air for long periods of time. Large amounts of rust will fall into the tank and clog the filter socks and ruin the pumps.
http://i190.photobucket.com/albums/z224/A26B/FuelPumpAssy.jpg

[Zr1 Destroyer]

Ewwww:cry:

[Randall1]

Now that is ugly

[TonyTZR1]

I had the same problem with the 90 I bought. The car was stored for over a year, bad injectors. Replaced them all is well.

[Randall1]

Well, I pulled a code 15 (low coolant sensor) but can't believe that makes the car very hard to start, backfire, stumble etc. Of course that sensor in under the plenum so I will start ordering parts beginning with new injectors that can handle the newer fuel, new coils, spark plug wires and gaskets. I will not start the job until all parts have arrived based on all the reading from this forum. I am on a mission now so this should get interesting.

Randall

[Jeffvette]

Well, I pulled a code 15 (low coolant sensor) but can't believe that makes the car very hard to start, backfire, stumble etc. Of course that sensor in under the plenum so I will start ordering parts beginning with new injectors that can handle the newer fuel, new coils, spark plug wires and gaskets. I will not start the job until all parts have arrived based on all the reading from this forum. I am on a mission now so this should get interesting.

Randall

Randall, give me a shout and let me know what you need. I have most of it in stock.

Jeff

[tf95ZR1]

Hey Randall
The parts aren't cheap. Unless you planned to replace
all those parts anyway, I'd isolate the problem first
and just replace what's necessary.

Save the extra $$ for mods. :dancing

And I would take Jeff up on his offer to come and check out your car.
I've heard he sometimes works for Diet Cokes. :cheers:

[Randall1]

I will be calling Jeff very soon.

[Nick]

And I would take Jeff up on his offer to come and check out your car.
I've heard he sometimes works for Diet Cokes. :cheers:
Actually, its root beer, no ice. :thumbsup:

[HADI-ZR1]

Randall,
You should always try to keep the tank completely full, especially when it's sitting for long periods of time. Here's what happens when the fuel pump assy is exposed to air for long periods of time. Large amounts of rust will fall into the tank and clog the filter socks and ruin the pumps.
http://i190.photobucket.com/albums/z224/A26B/FuelPumpAssy.jpg
Jerry , i am intersting in these aviation gauges , are those for sell?:mrgreen:
from which plane you took it off? :icon_scra
love the planes and jet since i was child and still...

[A26B]

Jerry , i am intersting in these aviation gauges , are those for sell?:mrgreen:
from which plane you took it off? :icon_scra
love the planes and jet since i was child and still...

Not for sale Hadi...came out of an F4 Phantom. I share your feelings for planes. I've had this "attachment for the Phantom" since Vietnam.