Another 94 LT1 with a hard start problem
10-17-2017, 02:38 PM
#21
Howdy howdy
I've been having problems with hard starts in my 94 LT1 for a while. It'll take a few cranks of the key, anywhere from 2-4, for the car to start when cold, and 1-2 tries when hot for it to start.
When it's cold, it'll start to catch and sputter on about the second try. Sometimes if I keep the key turned while it catches and sputters I can get it to turn over, but usually I'll have to cycle the key for another try. And very rarely, she'll turn over but her idle will drop to about 400-600rpms and the car shutters pretty badly, and then dies.
I've been having problems with hard starts in my 94 LT1 for a while. It'll take a few cranks of the key, anywhere from 2-4, for the car to start when cold, and 1-2 tries when hot for it to start.
When it's cold, it'll start to catch and sputter on about the second try. Sometimes if I keep the key turned while it catches and sputters I can get it to turn over, but usually I'll have to cycle the key for another try. And very rarely, she'll turn over but her idle will drop to about 400-600rpms and the car shutters pretty badly, and then dies.
Also, after the fuel pump replacement, I would change the filter yearly, even if it don't need it. I have had to replace two and now I bumped up the maintenance of the filter to annual changes.
10-17-2017, 03:07 PM
#22
Team Owner
Should have bought it from Racetronix since it comes complete with gaskets and SS hex bolts, IIRC. When replaced the pulsator what hose did you use?
10-17-2017, 04:37 PM
#23
Racer
Thread Starter
It was a piece that came in the Delphi fuel pump, it had a replacement gasket for the spot between the pump and the strainer, a replacement rubber-ish sleeve, 2 plastic clamps, the fuel pump, and two big O-ring style gaskets which I still cannot find a use for. The hose was pretty thick and dense, I couldn’t get it to collapse or hardly bend, and it clamped over the pipe and pump nicely.
10-17-2017, 04:44 PM
#24
Team Owner
It was a piece that came in the Delphi fuel pump, it had a replacement gasket for the spot between the pump and the strainer, a replacement rubber-ish sleeve, 2 plastic clamps, the fuel pump, and two big O-ring style gaskets which I still cannot find a use for. The hose was pretty thick and dense, I couldn’t get it to collapse or hardly bend, and it clamped over the pipe and pump nicely.
10-17-2017, 05:06 PM
#25
Racer
Thread Starter
If the new fuel pump doesn't solve the issue, I would suggest your MAF. When my MAF sensor failed on me in traffic, my idle suddenly dropped below 1000 and then the engine quit. I had to start the car up and keep the throttle partially open to avoid the engine dying on me. Starting up was also a pain and this was with the engine at operating temperature! This is just my input from personal experience.
Also, after the fuel pump replacement, I would change the filter yearly, even if it don't need it. I have had to replace two and now I bumped up the maintenance of the filter to annual changes.
Also, after the fuel pump replacement, I would change the filter yearly, even if it don't need it. I have had to replace two and now I bumped up the maintenance of the filter to annual changes.
She stills runs less than what I would consider optimal, especially when she’s really hot. Replacing the MAF may be my next step, I also need to replace plugs and wires since I’ve got no idea when they were last replaced. I’m still kicking myself for not replacing them when I did the opti and getting it all over with at one time
I’m not trying to throw just throw parts at her in hopes it fixes all her problems. I’ve got no history on her and what’s been done, and given the age of the car I figure it’s better to do preventative maintenance when I’m in an area and build a history on her rather than let it go until it breaks and risk something else breaking because of it
10-17-2017, 05:31 PM
#26
Racer
Thread Starter
How would you tell if it’s rated for immersion?
10-17-2017, 08:54 PM
#27
Team Owner
The new pump and pulsator seem to at least fix the pressure problem I was having. When I key on it shoots up to just about 40 and stays there for hours, and now she turns over almost instantly when cold. Hot takes a tad longer, maybe about a half or full second longer, but then she fires up. It’s worlds better than the stuttering and sputtering she used to do when I’d start her after work or in the morning, or any time really
She stills runs less than what I would consider optimal, especially when she’s really hot. Replacing the MAF may be my next step, I also need to replace plugs and wires since I’ve got no idea when they were last replaced. I’m still kicking myself for not replacing them when I did the opti and getting it all over with at one time
I’m not trying to throw just throw parts at her in hopes it fixes all her problems. I’ve got no history on her and what’s been done, and given the age of the car I figure it’s better to do preventative maintenance when I’m in an area and build a history on her rather than let it go until it breaks and risk something else breaking because of it
She stills runs less than what I would consider optimal, especially when she’s really hot. Replacing the MAF may be my next step, I also need to replace plugs and wires since I’ve got no idea when they were last replaced. I’m still kicking myself for not replacing them when I did the opti and getting it all over with at one time
I’m not trying to throw just throw parts at her in hopes it fixes all her problems. I’ve got no history on her and what’s been done, and given the age of the car I figure it’s better to do preventative maintenance when I’m in an area and build a history on her rather than let it go until it breaks and risk something else breaking because of it
I'd replace the plugs with an average life plug. Toss them after a year or so. When they come out, you can check the condition for oil or coolant in the combustion chamber. Can't really read the condition for lean or rich much since EFI changes the mixture constantly. I would interrogate the O2 sensor for that information. If you think the wires are bad, start it cold in a dark garage and spray a fine mist of water around the wires and see what it does. Also repeat test after a drive so the engine gets to temp. You should see nothing.
Fluids are definitely bad to run for too long and those I would change. O2 sensor if it is a few years old or uncertain. MAF I'd hold off. I am not sure of the quality of the cheap parts store ones so either get an OE or Bosch one or I'd keep what I have and spray with a fine mist of MAF cleaner.
10-17-2017, 08:54 PM
#28
Team Owner
11-18-2017, 03:10 PM
#29
Racer
Thread Starter
Ok, so I'm gonna dig this thread up, since it's kind of related to the same problem and creating a new post would just cram up the general section.
The vette still turns over on the first time, replaced the regular hose that came with the pump for some 3/8's immersion line cause pressure started to crap out again, used metal clamps instead of the plastic ones and she starts right up.
But, one of the problems that really made me think the pump was bad is still occuring. During startup, if the car is warm or been run and moved around for about 5 minutes, the engine will start stumbling, the RPM's will go down to about 400-500, and the car will start running like crap while they dip, but then it'll surge back up for a second or so, then it starts to stumble and dip, rinse and repeat. If I put it into gear, I can sometimes avoid it, but the other day it happened right as I was getting it into gear and lasted until I started getting up and moving. If it's idling and it starts stumbling, I can try and give it gas, and sometimes it'll respond, but sometimes it won't.
I'm wondering if maybe it's the TPS, cause when she starts up the engine will immediately increase idle to about 1600-2100 RPM's, then slowly drop down. I was also thinking maybe it's the IACV, though it was replaced about 3-4 months ago, at the same time I replaced the Opti, the pump and the thermostat. It's a cheap part so I don't mind ordering a new one to test it, but what's the best way to go about diagnosing this? I'm replacing plugs and wires tomorrow to try and get rid of the misfire it feels like it's having, the wires look like crap, and while they're kept away from the manifolds and the block at the plugs, they're routed all over the place going to the opti. I didn't see any sparks going between them when I misted the wires, but I figure it's still a good idea to get them done.
The vette still turns over on the first time, replaced the regular hose that came with the pump for some 3/8's immersion line cause pressure started to crap out again, used metal clamps instead of the plastic ones and she starts right up.
But, one of the problems that really made me think the pump was bad is still occuring. During startup, if the car is warm or been run and moved around for about 5 minutes, the engine will start stumbling, the RPM's will go down to about 400-500, and the car will start running like crap while they dip, but then it'll surge back up for a second or so, then it starts to stumble and dip, rinse and repeat. If I put it into gear, I can sometimes avoid it, but the other day it happened right as I was getting it into gear and lasted until I started getting up and moving. If it's idling and it starts stumbling, I can try and give it gas, and sometimes it'll respond, but sometimes it won't.
I'm wondering if maybe it's the TPS, cause when she starts up the engine will immediately increase idle to about 1600-2100 RPM's, then slowly drop down. I was also thinking maybe it's the IACV, though it was replaced about 3-4 months ago, at the same time I replaced the Opti, the pump and the thermostat. It's a cheap part so I don't mind ordering a new one to test it, but what's the best way to go about diagnosing this? I'm replacing plugs and wires tomorrow to try and get rid of the misfire it feels like it's having, the wires look like crap, and while they're kept away from the manifolds and the block at the plugs, they're routed all over the place going to the opti. I didn't see any sparks going between them when I misted the wires, but I figure it's still a good idea to get them done.