Idle surge...problem still not solved

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Idle surge...problem still not solved

Reply #30 – June 15, 2006, 12:59:39 PM

when i start mine up it runs1200 1400 tnd then drops down to 800 but after that it wants to drop to 400 or alittle lower and jump up to1400 again but if i keep my foot on the gas while it warms up so it revs at 1200 and then shift into gear its fine till i get to the end of my street and it wants to blog and struggle to move then it goes. but after i drive for a while it and go to back up in to the driveway it dies.

Idle surge...problem still not solved

Reply #31 – June 15, 2006, 08:20:10 PM

ok Im starting to think TurboCoupe50 might be onto something with the computer thing.

cougar86_89 which computer do you got?
I have an old V8 XR7 computer from an 88 or at least thats what the salvage yard or whoever had wrote on the case.
Sick88TBird has one from an LSC.
all this and we all have similar problems. where as people with say the A9L computers are running like theyre supposed to.

Could it be possible in some weird way that we have to have certain computers to make the 5.0 SEFI engines work in our cars? Not that I'm that eager for a reason to get a new computer just yet. But could it be possible until we get a certain computer we're going to have problems similar to these?

Idle surge...problem still not solved

Reply #32 – June 15, 2006, 11:08:26 PM

Probably gonna just have to deal with it...how does grounding that test wire bump up fuel pressure??? BTW, these are not sequential EFI engines xzavior.

Idle surge...problem still not solved

Reply #33 – June 16, 2006, 11:07:56 AM

Quote from: Sick88Tbird

BTW, these are not sequential EFI engines xzavior.

Wrong answer.... ALL passenger car 5.0s are SEFI from '86-up. The trucks and vans were batch fire into the '90s...

Idle surge...problem still not solved

Reply #34 – June 16, 2006, 01:28:14 PM

Quote from: TurboCoupe50

Wrong answer.... ALL passenger car 5.0s are SEFI from '86-up. The trucks and vans were batch fire into the '90s...

Whoops, thought that applied to the passenger cars as well...I stand corrected. *inserts foot in mouth* boot leather doesn't really taste that bad...lol. Am I supposed to leave that tan/green wire grounded or just in a KOEO to set it up?

thanks,
Don

Idle surge...problem still not solved

Reply #35 – June 16, 2006, 04:24:28 PM

Quote from: Sick88Tbird

Whoops, thought that applied to the passenger cars as well...I stand corrected. *inserts foot in mouth* boot leather doesn't really taste that bad...lol. Am I supposed to leave that tan/green wire grounded or just in a KOEO to set it up?

thanks,
Don

Just to set pressure KOEO... DO NOT LEAVE IT CONNECTED....

Idle surge...problem still not solved

Reply #36 – June 16, 2006, 09:07:47 PM

i have the stock computer in an 86 ls 5.0 i dont know anything esle about it *(declare ignorance)*. did different one come from the factory?

Idle surge...problem still not solved

Reply #37 – June 16, 2006, 10:37:36 PM

no but what Im thinking is if we've upgraded the engine, for example, HO intake, HO tb, new exhaust and so on and so on, could that be making a difference as it lets the engine get more airflow and able to breathe easier.
Could it be possible the older computers cant compensate for it totally?
Im actually pretty lost on what could be wrong but I have noticed a difference between people with newer computers and people with older and so on.

Idle surge...problem still not solved

Reply #38 – June 17, 2006, 12:21:41 AM

Quote from: TurboCoupe50

Just to set pressure KOEO... DO NOT LEAVE IT CONNECTED....

Well, my fuel pressure according to the rail mounted gauge sits at 38lbs, so I figured I didn't need to perform that procedure...I would check those pin locations at the PCM, its easy enough as it's laying on my floor...but I don't feel comfortable messing with that...knowing my luck something horrible would happen.

It SOUNDS like my EGR is opening/closing when it surges low...when inside the car, I hear a funny tone by the firewall when it surges low...right were the EGR is. I don't think that is normal, but I've proven a few posts ago that I DON'T know it all...lol. TurboCoupe50, I know I'm a PITA, but I greatly appreciate your time and knowledge.

Thanks again,
Don

Idle surge...problem still not solved

Reply #39 – June 17, 2006, 11:13:15 AM

Disconnect the vac to the EGR... It will run fine without it... If it still surges that ain't your problem... If your F/P is 38 psi with the vac line on the reg then it's too high... Set at 39 with NO vac, then try +/- a pound or two from that point...

The Speed Densety EECs can only compensate SLIGHTLY for engine changes... You may get away with a larger throttle body and/or exaust. But beyond that, airflow improvements will cause a lean condition at WOT. Larger injectors will cure that problem, but it will be pig rich at idle... Possibly a slight increase in F/P(with orig injectors) will be OK...

Idle surge...problem still not solved

Reply #40 – June 17, 2006, 12:48:44 PM

mine also makes a click noise put is isnt as load as a lifter like my dads car has put could that be part of the problem?

Idle surge...problem still not solved

Reply #41 – June 17, 2006, 05:18:08 PM

mine ticks too. could you happen to have an exhaust leak? my passenger side where the tail pipe meets the header is leaking and it sounds like a ticking or clicking sound. only reason I know its the exhaust is I can feel the air coming out if I put my hand by it. try when you first start it if you start looking for one though so you dont burn yourself.

Also are the stock HO and stock SO injectors the same size?

Idle surge...problem still not solved

Reply #42 – June 17, 2006, 09:40:16 PM

Quote from: TurboCoupe50

Disconnect the vac to the EGR... It will run fine without it... If it still surges that ain't your problem... If your F/P is 38 psi with the vac line on the reg then it's too high... Set at 39 with NO vac, then try +/- a pound or two from that point...

It's at 38lbs with the KOEO...at idle, with the vac connected it's at approx. 32-33lbs...at idle without the vac line connected it's at approx 42-43lbs.

I know for a fact the HO and SO injectors are different...stock HO injectors(not cobra) are 19lb/hr whereas SO injectors are 14lb/hr. I will try disconnecting the vacuum line to the EGR...I doubt it will help but it's easy enough to try....my full-length headers are of the "slip-fit primary" design and they leak a little...but the car was doing this well before I had those headers on. So, I don't think that a slight exhaust leak will cause such a problem.