crossfire surges at idle
Melting Slicks
Joined: Aug 2003
Posts: 3,416
Likes: 291
From: dayton oh
I looked up your cam and it looks to be the CC XFI260. From what i've read from other 82 modifiers experience, any cam above 210 duration on the intake side doesnt play well with the CPU..... your cam is at 216.
also, maybe i missed it, but you would HAVE to upgrade your fuel pump (85-89 Vet TPI pump) to keep up with your higher perf rebuilt motor.
The stocker can BARELY feed the stock 200hp engine.
These pts in addition to all the other advice posted above !
also, maybe i missed it, but you would HAVE to upgrade your fuel pump (85-89 Vet TPI pump) to keep up with your higher perf rebuilt motor.
The stocker can BARELY feed the stock 200hp engine.
These pts in addition to all the other advice posted above !
Last edited by Fast81; Nov 29, 2018 at 08:36 AM.
Thread Starter
Heel & Toe
Joined: Jul 2017
Posts: 18
Likes: 1
From: Spring Hill KANSAS
I tried the paper method with the throttle bodies and they both appear to be the same.
According to tracking I should receive the fuel pressure gauge i ordered on saturday and plan to see what fuel pressure I actually have on Sunday.
The speedometer cable arrived today and I will put in this eve so at least the vss will have a signal.
I also plan to put the bored throttle bodies back on this weekend and see if I can drive it around a bit to see if the IAC's will set.
The data sheet for the cam does show 216 duration on the intake side and 223 on the exhaust side. I hate to replace a new cam but if what I have is not correct I will change the cam to something that will work. I think I will change to the renegade intake at the same time.
Any suggestions on what cam to put in?
According to tracking I should receive the fuel pressure gauge i ordered on saturday and plan to see what fuel pressure I actually have on Sunday.
The speedometer cable arrived today and I will put in this eve so at least the vss will have a signal.
I also plan to put the bored throttle bodies back on this weekend and see if I can drive it around a bit to see if the IAC's will set.
The data sheet for the cam does show 216 duration on the intake side and 223 on the exhaust side. I hate to replace a new cam but if what I have is not correct I will change the cam to something that will work. I think I will change to the renegade intake at the same time.
Any suggestions on what cam to put in?
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,754
From: Charlotte NC
AGREED...it has been proven that getting fuel pressure up more can help.
IF you do plan on doing this known fuel pump conversion and adjusting your fuel pressure. I would suggest that you also replace the rubber hoses and the sending unit with better ones. Normal 3/8" fuel hose is rated a 50 psi (as I have been told). Then new fuel pump is right at that pressure. So when I do this I use the bio fuel hose which is rated at about 220 psi....just to be safe.
YES..I am aware that the rubber hose GM used for the 1985 to 1991's seemed to be the same as normal fuel hose where it was crimped to the steel line...but why take the chance.
The same holds true where your steel lines need a rubber hose the engine also.
I am only worried about the pressure side. But if you want to do the return also... it would not hurt.
DUB
IF you do plan on doing this known fuel pump conversion and adjusting your fuel pressure. I would suggest that you also replace the rubber hoses and the sending unit with better ones. Normal 3/8" fuel hose is rated a 50 psi (as I have been told). Then new fuel pump is right at that pressure. So when I do this I use the bio fuel hose which is rated at about 220 psi....just to be safe.
YES..I am aware that the rubber hose GM used for the 1985 to 1991's seemed to be the same as normal fuel hose where it was crimped to the steel line...but why take the chance.
The same holds true where your steel lines need a rubber hose the engine also.
I am only worried about the pressure side. But if you want to do the return also... it would not hurt.
DUB
Safety Car
Joined: Nov 2005
Posts: 3,532
Likes: 1,185
From: Arizona - If you don’t know CFI, STOP proliferating the myths around it...
I looked up your cam and it looks to be the CC XFI260. From what i've read from other 82 modifiers experience, any cam above 210 duration on the intake side doesnt play well with the CPU..... your cam is at 216.
also, maybe i missed it, but you would HAVE to upgrade your fuel pump (85-89 Vet TPI pump) to keep up with your higher perf rebuilt motor.
The stocker can BARELY feed the stock 200hp engine.
These pts in addition to all the other advice posted above !
also, maybe i missed it, but you would HAVE to upgrade your fuel pump (85-89 Vet TPI pump) to keep up with your higher perf rebuilt motor.
The stocker can BARELY feed the stock 200hp engine.
These pts in addition to all the other advice posted above !
So, whoever said the cam listed is NOT the issue is wrong, sorry, jus sayin'. If this is not the cam you have, please post the correct PN and full cam card spec, thanks.
If you decide to run the stock FPR, I would suggest that you not do that and go the parallel plumb route with an external regulator and block off plates which will eliminate the bladders in both TBs, then you won't have to worry about the FP at the TBs and rupturing the bladders and have gas going everywhere on a hot motor.
Last edited by Buccaneer; Nov 30, 2018 at 04:44 PM.
Safety Car
Joined: Nov 2005
Posts: 3,532
Likes: 1,185
From: Arizona - If you don’t know CFI, STOP proliferating the myths around it...
I tried the paper method with the throttle bodies and they both appear to be the same.
According to tracking I should receive the fuel pressure gauge i ordered on saturday and plan to see what fuel pressure I actually have on Sunday.
The speedometer cable arrived today and I will put in this eve so at least the vss will have a signal.
I also plan to put the bored throttle bodies back on this weekend and see if I can drive it around a bit to see if the IAC's will set.
The data sheet for the cam does show 216 duration on the intake side and 223 on the exhaust side. I hate to replace a new cam but if what I have is not correct I will change the cam to something that will work. I think I will change to the renegade intake at the same time.
Any suggestions on what cam to put in?
According to tracking I should receive the fuel pressure gauge i ordered on saturday and plan to see what fuel pressure I actually have on Sunday.
The speedometer cable arrived today and I will put in this eve so at least the vss will have a signal.
I also plan to put the bored throttle bodies back on this weekend and see if I can drive it around a bit to see if the IAC's will set.
The data sheet for the cam does show 216 duration on the intake side and 223 on the exhaust side. I hate to replace a new cam but if what I have is not correct I will change the cam to something that will work. I think I will change to the renegade intake at the same time.
Any suggestions on what cam to put in?
Here is a cam I also ran for about 5-6 years in the beginning. It's a single pattern cam, not a power house cam, but it does run well and is stock ECM friendly and likes chip mods. Run 1.6 rockers for a bit more lift if you like which should put it roughly .470ish. Just a suggestion, there are plenty of others out there to choose from.
Last edited by Buccaneer; Nov 30, 2018 at 04:43 PM.
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Thread Starter
Heel & Toe
Joined: Jul 2017
Posts: 18
Likes: 1
From: Spring Hill KANSAS
I am going to check fuel pressure on Sunday and see where I am there. I did replace the fuel pump. I was told it was a higher pressure pump.
I will know for sure once I see exactly where my pressure is.
Based on the added information about the ecu should I worry about cam at this point?
I will know for sure once I see exactly where my pressure is.
Based on the added information about the ecu should I worry about cam at this point?
Thread Starter
Heel & Toe
Joined: Jul 2017
Posts: 18
Likes: 1
From: Spring Hill KANSAS
I connected a fuel pressure gauge between the throttle bodies and I only have 8 psi fuel pressure. I am going to need to replace the fuel pump with a better one. I am going to see if I can get one yet today and install it and see what pressure I can get
Let me know if you have any questions.
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,754
From: Charlotte NC
Glad you took the effort to check the fuel pressure due to how important actually is.
And if my memory serves me correctly...GM installed a block off plate that stops you from adjusting the fuel pressure from that of the factory setting. It more than likely may need to be taken apart to remove it. You can use a small mirror to see if the block off plate is installed or not.
DUB
And if my memory serves me correctly...GM installed a block off plate that stops you from adjusting the fuel pressure from that of the factory setting. It more than likely may need to be taken apart to remove it. You can use a small mirror to see if the block off plate is installed or not.
DUB
Melting Slicks
Joined: Aug 2003
Posts: 3,416
Likes: 291
From: dayton oh
One other possible contributing factor: what cc are those rebuilt "double hump" head chambers?
If they are the usual 62cc sizes, your DCR would be around 10.4:1 which would be high (detonation) with iron heads...............................
If they are the usual 62cc sizes, your DCR would be around 10.4:1 which would be high (detonation) with iron heads...............................
Last edited by Fast81; Dec 3, 2018 at 11:20 AM.