After cam install, my V-8 is a 4cyl
After cam install, my V-8 is a 4cyl
Got the new cam installed, and got it to fire up, but it was missing really-really bad. I let it run for 20mins this way, just so I could break in the cam. After adjusting the valves, and setting the timing, it still ran like crapola. I started pulling spark plug wires, and I could pull #1, #3, #6, and #7 all off at the same time, still ran the same!!! Any other wires, it wanted to die. So I went back to ground zero. Noticed the timing chain markes were both set at 12 o'clock. This is how I pulled out the old cam, so this is how the new one went in. So, then I repositioned it with it dot-to-dot. Repositioned the distributor, and tried again. Backfire, spit, sputter, but it didn't want to kick over. Moved the wire around 180*, and It wont fire over, but at least it acts more like it wants to. What am I missing? It should be set dot-to-dot, not 12 & 12. And with it at 12 & 12, four cylinders aren't firing. Oddly enough, its all four wires of the distributor that are on the drivers side.
I've driven myself crazy pulling plug wires to try to determine what's firing and what's not. Just put that aside and forget about it.
You can install the cam dot-to-dot or 12-to-12. Makes no difference except that dot-to-dot you're on TDC compression of #6 and 12-to-12 your on TDC compression of #1.
It's easier to make sure you're truly and perfectly lined up when you do it dot-to-dot since they're right next to eachother at that point.
This could be part of the reason you're not running right, though. If you're setting the valves on #1 cylinder when you're actually on the exhaust stroke of #1 instead of intake you'll DEFINITELY have them set wrong.
I really suspect that the valves aren't set right. Do it with the engine running- get some rocker arm clips and expect to get some oil on the exhaust (unless you have a spare valve cover with the top cut off it like I do for exactly this procedure). Back 'em off one at a time till they tap, then tighten till it stops, then 1/2 turn more.
99 times out of 100 this is the reason the engine is missing after a cam swap.
Engine won't run with the distributor off by 180*, btw. Old wive's tale. It'll just "cough" through the intake every now and then.
You can install the cam dot-to-dot or 12-to-12. Makes no difference except that dot-to-dot you're on TDC compression of #6 and 12-to-12 your on TDC compression of #1.
It's easier to make sure you're truly and perfectly lined up when you do it dot-to-dot since they're right next to eachother at that point.
This could be part of the reason you're not running right, though. If you're setting the valves on #1 cylinder when you're actually on the exhaust stroke of #1 instead of intake you'll DEFINITELY have them set wrong.
I really suspect that the valves aren't set right. Do it with the engine running- get some rocker arm clips and expect to get some oil on the exhaust (unless you have a spare valve cover with the top cut off it like I do for exactly this procedure). Back 'em off one at a time till they tap, then tighten till it stops, then 1/2 turn more.
99 times out of 100 this is the reason the engine is missing after a cam swap.
Engine won't run with the distributor off by 180*, btw. Old wive's tale. It'll just "cough" through the intake every now and then.
Sounds like you screwed up the timing, lash, or firing order. It doesn't really matter if you set the cam relative to the crank dot to dot or both at 12 o'clock, you just have to set the distributor right.
Only thing I can think of now, is to reset the timing, recheck all the wiries and the distributor cap. If that still isn't working, pull a valve cover and make sure the lash is right. I'm sure you've done this. But do it again. You want your lash to be about half a turn past 0 lash, when the pushrod first stops spinning freely as you tighten it. Timing doesn't matter because you can't measure it if the engine doesn't run, just get it close and leave the dist loose so you can experiment.
Anything else we need to know?
Only thing I can think of now, is to reset the timing, recheck all the wiries and the distributor cap. If that still isn't working, pull a valve cover and make sure the lash is right. I'm sure you've done this. But do it again. You want your lash to be about half a turn past 0 lash, when the pushrod first stops spinning freely as you tighten it. Timing doesn't matter because you can't measure it if the engine doesn't run, just get it close and leave the dist loose so you can experiment.
Anything else we need to know?
When I did have it running the first time, I set the lash by backing off untill the rocker taped, turned untill noise stopped, then gave it 1/4 turn more. This is why I don't think this is the problem: It was missing from the very get go, and even after setting the lash, and putting the timing at 8* (with wire unpluged), it still was missing like all crazy. Don't you find it weard how its only running on 4 cylinders. The others are getting spark, because as I pull the wire off the cap, the spark does jump. Funny thing is though, I can't get it to start back up again, even on the 4 cylinders, it acts like it want's to, but not quite. Any more suggestions???
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From: USA
Car: yy wife, crazy.
Engine: 350, Vortecs, 650DP
Transmission: TH-350
Axle/Gears: 8.5", 3.42
Are you sure the dissy and the dissy cap are seated all the way in and are flat?
The reason I ask is because the cylinders you say are not making a big difference are VERY close together in the firing order. #3 and #6 especially.
1 8 4 3 6 5 7 2
If the oil pump drive shaft coming from the bottom on the dissy isn't perfectly seated in the "notch" on the bottom of the dissy, then the dissy will be cocked to one side. That's not very likely to cause the firing problem, but what is?
If you unknowingly tried to get the CAP to set level, then IT may be cocked also. This would keep those terminals farther from the rotor while it's spinning that way. This would cause erratic ignition since some arc may make the jump, some may not.
Or it could just be the cap is on crooked. Or it's just simply worn out.
The reason I ask is because the cylinders you say are not making a big difference are VERY close together in the firing order. #3 and #6 especially.
1 8 4 3 6 5 7 2
If the oil pump drive shaft coming from the bottom on the dissy isn't perfectly seated in the "notch" on the bottom of the dissy, then the dissy will be cocked to one side. That's not very likely to cause the firing problem, but what is?
If you unknowingly tried to get the CAP to set level, then IT may be cocked also. This would keep those terminals farther from the rotor while it's spinning that way. This would cause erratic ignition since some arc may make the jump, some may not.
Or it could just be the cap is on crooked. Or it's just simply worn out.
Last edited by AJ_92RS; Apr 28, 2003 at 10:55 PM.
Also one of the things I've looked at a hundred times. To the best of knowledge, distributor is seated properly, cap and rotor are in good condition, wires are fine, plugs too. Thats also part of the weird problem, everything was running just fine before the cam swap.
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Joined: Apr 2001
Posts: 4,969
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From: USA
Car: yy wife, crazy.
Engine: 350, Vortecs, 650DP
Transmission: TH-350
Axle/Gears: 8.5", 3.42
OH..... I know now!!!! 
When you're working on the car, you have to move your wallet to your other pocket, tip your hat to one side, hang your tongue out the right side of your mouth, all while your humming "When the Saints go Marching In".
That should do it.
Seriously..... it sounds like one of those "Don't overlook the obvious" things. Check everything twice. And the things that your sure it can't be, check them THREE times.

When you're working on the car, you have to move your wallet to your other pocket, tip your hat to one side, hang your tongue out the right side of your mouth, all while your humming "When the Saints go Marching In".
That should do it.

Seriously..... it sounds like one of those "Don't overlook the obvious" things. Check everything twice. And the things that your sure it can't be, check them THREE times.
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From: SE Michigan
Car: Bright Red 91 GTA
Engine: CARBED LT4
Transmission: MK6
You can install the cam dot-to-dot or 12-to-12. Makes no difference except that dot-to-dot you're on TDC compression of #6 and 12-to-12 your on TDC compression of #1.
this is what id bet on...when your adjusting the intake valve on number 1 you should be getting the #6
Ok, I'm at my wits end now. I've reset the timing chain to 12 and 12. Restabed the distributor, and marked #1. Reset the wires, ensuring that the distributor rotated in a clockwise position, and placed the wires in a clockwise rotation. Double check 2 wires and 2 plugs that were not firing before. The plugs looked like they were almost fouled out. I sanded them slightly, and ensured that they were receiving spark. I try and try, and it just wont kick over now. The best I got was giving it full throttle, it sputterd at about 500 rpms for about 20 seconds. I even tried cranking it over while spraying carb cleaner in the pleneum, no help at all. I even pulled a plug that wasn't firing, and did a compression check, 150psi. I did observe that for those 20 seconds it did run, I checked the drivers side exhaust. And just as expected, #3 was hot, the other ice cold. It doesn't fire on 5-7-2-1. HELP!!!
ok im here, never fear, ill fix your problem. first of all, put the cam in the EXACT way it came out, ...make sure your dist is in right, all wires are in the right places. take your valve cover off the drivers side, ....bump the engine over and go look at yout timing mark,..keep doing this til the timing mark is on 0 , look at your valves, ...BOTH would be closed on the #1 cyl, ....feel for the piston to be at TDC in the #1 plug hole, ...its its there, drop the dist in, ...with the rotor facing the #1 plug, ....should be at about 5 olcock if you are facing the engine... if that doesnt work, ...guess what.. TRY IT AGAIN!!! thats right, it once took me two whole days to get my damn timing back on...so, ..keep trying, ..and try and try and try ..everything.....you can make sure your cam is in right by following the TDC instructions i just mentioned, and line the dots up DOT TO DOT...--when i stalle my cam i damn near failed to notice the dots and almost got in your situation, then i though oh yeah, read the manual lol...so get yourself a manual next time, and KEEP AT IT, youlll get it.....promise
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Joined: Apr 2001
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From: USA
Car: yy wife, crazy.
Engine: 350, Vortecs, 650DP
Transmission: TH-350
Axle/Gears: 8.5", 3.42
See..... now you're confusing him. 
The dots are gonna be lined up BOTH at the 12 o'clock position when the #1 cylinder is on the compression stroke. Don't mention that again because that's the way it is. There is no other way.
You are right about the balancer and the timing pointer though. That's the only true way to find TDC IF and only IF the outer ring on the balancer hasn't moved. It happens.
Overall, it sounds like you have a few injectors that aren't squirting the right amount of fuel (either too much or too little). Make sure the connections to them are secure, and they're completely attached to the fuel rail(s).
Based on all the things you've tried it sounds like they're the culprits.
About the only other thing I can think of is... the lobes on the cam worn down REALLY far during break in. Bust out with the dial indicator and measure how much lift each lobe has.
One other possibility is the cylinder(s) isn't sealing. I know it sounds far fetched, but I've had stranger things happen. It wouldn't hurt to do a compression or a leak down check.

The dots are gonna be lined up BOTH at the 12 o'clock position when the #1 cylinder is on the compression stroke. Don't mention that again because that's the way it is. There is no other way.
You are right about the balancer and the timing pointer though. That's the only true way to find TDC IF and only IF the outer ring on the balancer hasn't moved. It happens.

Overall, it sounds like you have a few injectors that aren't squirting the right amount of fuel (either too much or too little). Make sure the connections to them are secure, and they're completely attached to the fuel rail(s).
Based on all the things you've tried it sounds like they're the culprits.
About the only other thing I can think of is... the lobes on the cam worn down REALLY far during break in. Bust out with the dial indicator and measure how much lift each lobe has.
One other possibility is the cylinder(s) isn't sealing. I know it sounds far fetched, but I've had stranger things happen. It wouldn't hurt to do a compression or a leak down check.
Last edited by AJ_92RS; May 1, 2003 at 04:06 PM.
I'm missing on 5-7-2-1 in the firing order. Sounds really weard that it is 4 in a row that fire, 4 that arn't. I've check the spark through the plug, its good, check the injector harness with a light, its good. I've check and can gauarante the dist is inline with the cam and crank, and that #1 is set correctly, and all the wires are in the correct spot. I just cant verify yet if the injectors are firing too much fuel, or not enough. Any ideas?
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From: SE Michigan
Car: Bright Red 91 GTA
Engine: CARBED LT4
Transmission: MK6
i would say that maybe you blew a fuse that controlls the passenger side
but that 2 is in there
do u remember when i said that the injectors were the problem?...
strange its come back to them
..
but that 2 is in there
do u remember when i said that the injectors were the problem?...
strange its come back to them
.. O.K. Now I'm confused. Are you missing on 1-5-7-2 or 1-3-6-7? It will probably make a difference in the diagnosis. Either way, the injectors are almost ruled out, since they are in different banks. Did you change the plugs after they were fuel-fouled? Gas-soaked plugs don't fire well, if at all.
Solved the problem!!!
MY CATS!!!!!!!!
Before I assembled the fuel rail, I had my injectors setting in a bag on a chair. Well, my cats knocked the bag on the ground. This was only a 1 foot drop, and with the trouble I was having, I wouldn't think that would take out 4 injectors. 1 or 2 maybe, but not 4. Well, IT DID. I took the injectors back to work yesterday, and 4 were flowing perfectly fine, and the other 4 didn't even spit out a drop.
MY CATS!!!!!!!!
Before I assembled the fuel rail, I had my injectors setting in a bag on a chair. Well, my cats knocked the bag on the ground. This was only a 1 foot drop, and with the trouble I was having, I wouldn't think that would take out 4 injectors. 1 or 2 maybe, but not 4. Well, IT DID. I took the injectors back to work yesterday, and 4 were flowing perfectly fine, and the other 4 didn't even spit out a drop.
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Joined: Apr 2001
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From: USA
Car: yy wife, crazy.
Engine: 350, Vortecs, 650DP
Transmission: TH-350
Axle/Gears: 8.5", 3.42
Damn *******!!!
They'll always mess up something when you're not looking and you won't figure it out until you've pulled a few strands of hair out of your head.
They'll always mess up something when you're not looking and you won't figure it out until you've pulled a few strands of hair out of your head.

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From: SE Michigan
Car: Bright Red 91 GTA
Engine: CARBED LT4
Transmission: MK6
had a feeling it was the injectors...
there couldnt of been anything that could of caused that much of a problem
the funny part is..your sitting on the couch watchin tv and u start hearing this rustling noise...it goes away then u hear it again..so u go down the hall and see what it is..u turn the corner and see 2 full rolls of paper towel open and completly unrolled on the floor..then the cats look up at you like "what?" and walk away like nothin happened...
what injectors are u gonna get?....dont go to the dealer..theyll want 80 bucks for each one
there couldnt of been anything that could of caused that much of a problem
the funny part is..your sitting on the couch watchin tv and u start hearing this rustling noise...it goes away then u hear it again..so u go down the hall and see what it is..u turn the corner and see 2 full rolls of paper towel open and completly unrolled on the floor..then the cats look up at you like "what?" and walk away like nothin happened...
what injectors are u gonna get?....dont go to the dealer..theyll want 80 bucks for each one
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From: Loveland, OH, US
Car: 4
Engine: 6
Transmission: 5
Don't mess around with the crappy factory injectors.
Get a set of used stock Mustang ones from somebody doing an upgrade, and send them to Rich at www.cruzinperformance.com and tell him they're going in a GM so he'll get you the right O-rings. You won't believe how much better your car will run. Did that to my wife's 4.9 Cadillac.... it was amazing.
Get a set of used stock Mustang ones from somebody doing an upgrade, and send them to Rich at www.cruzinperformance.com and tell him they're going in a GM so he'll get you the right O-rings. You won't believe how much better your car will run. Did that to my wife's 4.9 Cadillac.... it was amazing.
File under: strange but true mechanics stories. In a million years I would never have suspected that dropping some injectors a short distance would kill them. I mean, they LIVE in a high-vibration environment- you think they would be tougher than that.
Hey, whatever. As long as it runs and you're happy. I've had weird stuff like that happen and all that counts at the end of the day is that feeling of relief when you know you got it solved dead-bang.
Hey, whatever. As long as it runs and you're happy. I've had weird stuff like that happen and all that counts at the end of the day is that feeling of relief when you know you got it solved dead-bang.
3 things:
1> I took my injectors back to work, put marvel mystery oil in them, banged them against the table a couple times, and ran it through the sonic cleaner 5 times. Guess what, they work just fine now!
2> This this would be ok to still use?
3> Why would the Ford 19lbs be any diffarant then the GM 19lbs?
1> I took my injectors back to work, put marvel mystery oil in them, banged them against the table a couple times, and ran it through the sonic cleaner 5 times. Guess what, they work just fine now!
2> This this would be ok to still use?
3> Why would the Ford 19lbs be any diffarant then the GM 19lbs?
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Joined: Jul 1999
Posts: 18,457
Likes: 16
From: Loveland, OH, US
Car: 4
Engine: 6
Transmission: 5
3. They're not F*rd, they're Denso. F*rd just happens to be one of their customers. It also just happens that they're a vastly superior product. Better spray pattern, better control, they just work better.
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From: SE Michigan
Car: Bright Red 91 GTA
Engine: CARBED LT4
Transmission: MK6
lmfao@ gutted cats hahaha
well thanks vader that touched my heart
yea dude just get a used set of denso 19#'ers...there 19#/hour at 30 somthing psi so at the tpi pressure at 45 theyll be a little more like 22#/hour...
is that right guys or do i have that backwards?
well thanks vader that touched my heart
yea dude just get a used set of denso 19#'ers...there 19#/hour at 30 somthing psi so at the tpi pressure at 45 theyll be a little more like 22#/hour...
is that right guys or do i have that backwards?
Interesting.. Glad you found the problem. You didn't happen to run some bad old gas through those injectors, did you? I wonder if you could have tapped themcwith a screwdriver when installed and gotten them unclogged.
You know how some shipped things are treated,shimyspacearandsoppedworkin****!!!!!!!arhdamnkeyoard,Ipilledwaeriniearlier..ifanyonecanreadhayouareclever.
sorry about that. my keyboard has no keys now cuz i took it apart to dry ouy, this is difficult
You know how some shipped things are treated,shimyspacearandsoppedworkin****!!!!!!!arhdamnkeyoard,Ipilledwaeriniearlier..ifanyonecanreadhayouareclever.
sorry about that. my keyboard has no keys now cuz i took it apart to dry ouy, this is difficult
Last edited by rezinn; May 8, 2003 at 04:35 PM.
"Ford" SVO injectors are rated at 37 PSI. GM at 43 PSI. It's not THAT much of a difference but I would think that a 19lb SVO injector would be around 20-21lb on the GM fuel pressure spec.
Last edited by Damon; May 8, 2003 at 08:11 PM.
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