I still think it's a chip problem. On a side note though you need to make sure you DID NOT use any thread sealant on the CTS switch otherwise it cannot ground properly and therefor won't give an accurate reading to the ECM or none at all.
CK5
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Unable to Idle, runs ruff
- Thread starter pomai
- Start date
what is the CTS switch? is that the coolant temp switch?
Thank you for your help. i need to get this going.
Thanks, Ed
Thank you for your help. i need to get this going.
Thanks, Ed
If your talking about the coolant temp switch, I just checked, I DID, I used ARP thread sealer.
Would this contribute to the code 33?
I changed the MAP sensor and still got the same code, and yes, I cleared the ECM.
Would this contribute to the code 33?
I changed the MAP sensor and still got the same code, and yes, I cleared the ECM.
Yes, CTS is coolant temp switch. I don't know if the sealant is contributing to your problem but i would definately remove it. I had an issue with using thread sealant before i learned you should never use it on sensors.
The mechanic is saying that the lifters are bleeding down and thinks the lifters are the problem.
The other mechanic thinks that the 1.6 roller rockers are the problem, saying that these rockers are applying to much leverage and there for are too much for the lifters, and is recommending that the stock 1.5 rockers be reinstalled.
My question is, should the 1.6 rockers work with these heads, cam, spring and lifter combination.
Engine is a late model factory roller 4 blt main block, 383 rotating assembly, scat crank, 6” rods, JE forged 40 over pistons, World S/R torquer heads. JBA shorty headers
Cam is a small base circle Roller Comp Cam 08-304-8, .500/.510, Duration 266/276, Lobe Separation 114,
Comp cam 1.6 roller rocker
Valve springs
300lbs open
120lbs closed
Lifters are comp cam roller lifters.
The other mechanic thinks that the 1.6 roller rockers are the problem, saying that these rockers are applying to much leverage and there for are too much for the lifters, and is recommending that the stock 1.5 rockers be reinstalled.
My question is, should the 1.6 rockers work with these heads, cam, spring and lifter combination.
Engine is a late model factory roller 4 blt main block, 383 rotating assembly, scat crank, 6” rods, JE forged 40 over pistons, World S/R torquer heads. JBA shorty headers
Cam is a small base circle Roller Comp Cam 08-304-8, .500/.510, Duration 266/276, Lobe Separation 114,
Comp cam 1.6 roller rocker
Valve springs
300lbs open
120lbs closed
Lifters are comp cam roller lifters.
what ratio rocker did you use?
I'm running 1.6 ratio on my engine.
Honestly, you need a new mechanic as he is just "throwing" useless info out there for you.
Honestly, you need a new mechanic as he is just "throwing" useless info out there for you.
What brand lifters are you using?
Do you remember what valve spring presure open and closed for you heads?
I could'nt find your cam number on the Comp Cam web site (8-484-4) was this the corrrect Number?
Turned out that one of 2 of the problems was one injector spiting out much more fuel then the other. I gave him 2 new 454 injectors and it ran. vacume went from 5" to 17. Brian Harris said it should be between 18 and 20 for my cam. beside the lifter bleeding down the motor sounds realy good. it fires right up.
The engine builder and Brian Harris said they have hear of the Comp Cams roller lifters giving problems with bleeding down among other things.
I'm going to stay with the 1.6 rockers and replace the lifters. What do you think?
Thank you for responding agian,
Ed
My cam is a Comp Cam 8-464-8 and it is one of their XFI cams. Here is a linbk to the specs on it. http://compcams.com/Cam_Specs/CamDetails.aspx?csid=206&sb=0
I bought my lifters from Summit Racing and they are just the standard lifter (sealed power i believe). There are only 2 lifter companies that make EVERY lifter out there today. Johnson lifter company used to be the largest one there was but years ago their warehouse burnt down and you could not buy a lifter anywhere and then finally a new company (can't remember who it was) started making lifters and so they were once again available. I'm not sure if they are still around or not but Rhodes lifters were an anti pump-up lifter and were noisy as hell and gave tons of problems (pretty sure they have been gone for years now.
I bought my lifters from Summit Racing and they are just the standard lifter (sealed power i believe). There are only 2 lifter companies that make EVERY lifter out there today. Johnson lifter company used to be the largest one there was but years ago their warehouse burnt down and you could not buy a lifter anywhere and then finally a new company (can't remember who it was) started making lifters and so they were once again available. I'm not sure if they are still around or not but Rhodes lifters were an anti pump-up lifter and were noisy as hell and gave tons of problems (pretty sure they have been gone for years now.
I looked at your cam specs and I realize that I may have made a bad choice on my cam. Brian Harris suggested this cam. I was concerned about the operating RPM range. Yours is 1000 to 5000, my cam starts at 1400 to 5400, not were I need it. It’s to late know, I have no more money to spend on this motor. After looking at your cam card I’m feeling depressed about my cam choice.
The shop installed the 1.5 rockers and the problem was still there. the lifters were still bleading down. So were going to change the lifters, I was thinking of the GM performance lifters.
stay tuned, lets see what happens with the new lifters.
Thanks, Ed
The shop installed the 1.5 rockers and the problem was still there. the lifters were still bleading down. So were going to change the lifters, I was thinking of the GM performance lifters.
stay tuned, lets see what happens with the new lifters.
Thanks, Ed
So what makes you think a lifter or lifters are bleeding down?
The mystery continues, had my blazer towed to a second shop, everything checked and double checked, all test duplicated from the first shop. Vacuum is at 10", had to keep the 5.7 injectors in for the engine to idle, fuel pressure is at 10psi, cant go any higher then that, very fuel pressure sensitive.
After a little more then $2000.00 in towing and diagnostics for 2 shops, I tried what Brian Harris has been asking me about for almost a year, Oil pump, I ran a M-55 HV high volume oil pump, and Brian felt that this was the problem, so I installed a M-55 A, high pressure as he suggested. Motor ran the same, vacuum at 10".
this is what i found on a web site:
12. Oil pumps, I have decided to add this on the list as TOO many people when building engines put high volume oil pumps in their motors and don't do this for a few reasons. 1. You would need to run a 7qt oil pan or you will suck the stock pan empty with any spirited use. 2. It takes 20hp to turn a high volume pump at higher rpms over a std volume pump. 3. Unless you prep the block properly you will end up sending too much oil to the hydraulic lifters and pump them up too much causing vacuum issues and poor performance. I use a std volume, high pressure pump http://www.summitracing.com/parts/MEL-M55A/ and its better than stock TBI oil pump and will save us both a LOT of headaches
What kind of oil pumps are you guys running?
Could the oil volume or pressure be contributing to the low vacuum, 10”.
After a little more then $2000.00 in towing and diagnostics for 2 shops, I tried what Brian Harris has been asking me about for almost a year, Oil pump, I ran a M-55 HV high volume oil pump, and Brian felt that this was the problem, so I installed a M-55 A, high pressure as he suggested. Motor ran the same, vacuum at 10".
this is what i found on a web site:
12. Oil pumps, I have decided to add this on the list as TOO many people when building engines put high volume oil pumps in their motors and don't do this for a few reasons. 1. You would need to run a 7qt oil pan or you will suck the stock pan empty with any spirited use. 2. It takes 20hp to turn a high volume pump at higher rpms over a std volume pump. 3. Unless you prep the block properly you will end up sending too much oil to the hydraulic lifters and pump them up too much causing vacuum issues and poor performance. I use a std volume, high pressure pump http://www.summitracing.com/parts/MEL-M55A/ and its better than stock TBI oil pump and will save us both a LOT of headaches
What kind of oil pumps are you guys running?
Could the oil volume or pressure be contributing to the low vacuum, 10”.
If the vacuum reading is nice and steady then you have too much cam. Camshaft is what controls how much vacuum the engine produces, as the cam gets more radical the vacuum drops off. The only other thing that can cause low vacuum is a vacuum leak somewhere. If the vacuum reading isn't steady then you have leaking valves (time for a valve job as the valves aren't seating properly).
