91 missing, surging, runnin bad
Team Owner
Joined: Dec 2000
Posts: 21,092
Likes: 282
From: Phila., PA burbs
Re: 91 missing, surging, runnin bad (subman)
My '91 had very similar symptoms to the ones your describing and after pulling my hair out for awhile I also decided it looked like a few bad fuel injectors. I replaced the injectors with the Ford 24lb units and its now running great :cheers:
Drifting
Joined: Apr 2003
Posts: 1,379
Likes: 4
From: rome ny
Re: 91 missing, surging, runnin bad (TA)
sub ,those readings point to 3 bad injectors. the worst one i had was 7.5. those are real bad. just make sure you replace the all. if your engine code is 8 then it it is a 91, mine is 8 also.
Thread Starter
Burning Brakes
Joined: Jul 2003
Posts: 873
Likes: 2
From: Whittier ca
Re: 91 missing, surging, runnin bad (mos90)
Okay-I've found the injectors and I'm tearing down tonite - This will be my 1st attempt at changing injectors - - so the questions are:
1 - anything I should look for when taking thing apart that would indicate another problem?
2 - When puttin it back together, is there a certain sequence (aside from what would seem logical) to put it back togther?
3 - When seating the injector seals, should they be lubed with anything to help ease/fit/seal?
4 - Anything special at all?
I would hate to get it all together and find that a $3.00 item screwed things up.
Thanks for the help.
Subman
[Modified by subman, 4:06 AM 7/12/2003]
[Modified by subman, 4:06 AM 7/12/2003]
1 - anything I should look for when taking thing apart that would indicate another problem?
2 - When puttin it back together, is there a certain sequence (aside from what would seem logical) to put it back togther?
3 - When seating the injector seals, should they be lubed with anything to help ease/fit/seal?
4 - Anything special at all?
I would hate to get it all together and find that a $3.00 item screwed things up.
Thanks for the help.
Subman
[Modified by subman, 4:06 AM 7/12/2003]
[Modified by subman, 4:06 AM 7/12/2003]
Drifting
Joined: Apr 2003
Posts: 1,379
Likes: 4
From: rome ny
Re: 91 missing, surging, runnin bad (subman)
when your taking the old injectors out there is a clip the holds the top of the injector to thre fuel rail. you dont need them. it just makes the assembly litte easier, they are a bitch to get back on. most after market injectors will not have them. there is no specific order to install the injectors but i think its easier to put the passinger side one on first. also when the start to tighten the fuel rails down you should move each injector side to side to make sure they are not biding. with yhe oil or grease you put on the orings they should move fairly easy.
Race Director
Joined: Aug 2002
Posts: 13,356
Likes: 0
From: tucson AZ
St. Jude Donor '04 & '05
Re: 91 missing, surging, runnin bad (subman)
Checked your fuel pump?????
What pressures at the injectors?????
Just a thought...
tony
:smash: :smash: :smash:
[Modified by oldace84, 11:39 AM 7/12/2003]
What pressures at the injectors?????
Just a thought...
tony
:smash: :smash: :smash:
[Modified by oldace84, 11:39 AM 7/12/2003]
Racer
Joined: Aug 2000
Posts: 337
Likes: 1
From: Kennesaw,Georgia,USA Ga.
Re: 91 missing, surging, runnin bad (subman)
91 models were L-98s so they all ran with 9.5 compression right? Then in 92 the new LT-1s came out with the reverse cooling design and 10.5 compression engines. The intake on the LT-1 was then not the old tuned port design. My 87 car, I took the old EGR valve off and the solenoid which is mounted on the thermostat housing. My car is surging now all of the sudden and it points to a fuel problem I think. I has flat spots and acts like a carburated car with a bad accelerater pump. I'm going right out there now and check the resistance in those injectors. They are bosch 30lb. The car ran great for the last three years. Of course now I've been running the 383 with Superam ported and Dana 44 with 3.45s. Hopefully, reading all of your statements, I can fix mine too.
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Thread Starter
Burning Brakes
Joined: Jul 2003
Posts: 873
Likes: 2
From: Whittier ca
Re: 91 missing, surging, runnin bad (oldace84)
mos90-thanks for the info. All is clean and ready to re-install. Just got back from picking up injectors. Bosch 21#. fiveomotorsports.com is about 1/2 hour from my house and I picked them up there. Here's hoping.
oldace-replaced the fuel pump - had 42 lbswhen the ing. 1ST turned on, then down to 40. When running had 38-39 lb's constant. Also replace the fuel filter.
oldace-replaced the fuel pump - had 42 lbswhen the ing. 1ST turned on, then down to 40. When running had 38-39 lb's constant. Also replace the fuel filter.
Thread Starter
Burning Brakes
Joined: Jul 2003
Posts: 873
Likes: 2
From: Whittier ca
Re: 91 missing, surging, runnin bad (Blkvette87)
blkvette-after you check the ohms on the injectors, check the fuel pressure at the rail. Just curious, why did you remove the EGR and stuff? If you put all back on, would you 87 run any different. I would prob. check that before you change the injectors. Keep us posted
Subman
Subman
Racer
Joined: Aug 2000
Posts: 337
Likes: 1
From: Kennesaw,Georgia,USA Ga.
Re: 91 missing, surging, runnin bad (subman)
Yeah, I'll look into my EGR system. I was just trying to clean the engine compartment up some. I might have a problem there though. The tube running to the check valves were rotted and fell apart so I might just get a new one and reinstall the system again. Maybe my prom isn't programmed to operate without the system. My injectors all checked good resistance wise. I changed my filter and the car woke up some and I suspect my pump now as it is getting old. Thanks.
Thread Starter
Burning Brakes
Joined: Jul 2003
Posts: 873
Likes: 2
From: Whittier ca
Re: 91 missing, surging, runnin bad (subman)
mos90 - oh yes I did (LOL) see the following thread http://forums.corvetteforum.com/zerothread?id=609288
thanks for asking
Subman
Remember the wave
thanks for asking
Subman
Remember the wave
