Popping and misfire when under boost

[Quick6'n'-K.C.]

Quick6nK-C, care to elaborate?

Yeah i will elaborate... He did not do it correctly.

TDC #1, turn motor over 1 inch, drop cam sensor shaft over oil pump gear and follow directions i posted.

I see he said, "Replaced cam sensor...problem solved" and asked "Anybody know where I can get just the sensor without the whole assembly?"

Hmmmm Has the shaft actually been removed, and OR, tdc#1 with the cap off, roll the motor over and watch the window of oppertunity on each stroke of #1 Possible that the shaft is not in the correct spot and someone screwed up and dropped it in with the car actually at TDC #1 ?



BW

 

[BenPutnam]

I installed the new sensor in the same position as the old but never pulled or adjusted the assembly, I suppose I should 'time' it according to the directions if only to rule that out as a possible problem. I'm curious why installing it out of phase (backwards) seemed to fix the problem.

 

[rodman99999]

Check crank sensor for correct clearance on crank sensor. If sign of contact with interuptor replace sensor.

About that crank position sensor: Why will the car run fine until close to WOT with a bad one? I was thinking that the ignition depended on it for spark timing all the time?

 

[FreeBoost]

About that crank position sensor: Why will the car run fine until close to WOT with a bad one? I was thinking that the ignition depended on it for spark timing all the time?

Don't know why, but the crank sensor can be a source of a lot of problems and it's easy to check. Maybe it's out of alignment only slightly and at higher rpms the crank walks slightly and makes contact with the interuptor - I don't know. But like I said, it's easy to check.

 

[TurboBuRick]

About that crank position sensor: Why will the car run fine until close to WOT with a bad one? I was thinking that the ignition depended on it for spark timing all the time?

The crank signal is needed at all times. If you unplug it, the motor will not run.

 

[Mike70gtx]

Update on my original post. New fuel pump cured the backfiring and popping. Now it just doesn't pull like it used to. I kind of sounds like a big truck when they put on their jake brake. I have a caspers ignition tester to check the module and coil. The old module showed bad and the used one that I got from someone on here. So I go to town and buy a new ac delco ignition module and it test bad the exact same way as the others. The guy at caspers had me check a couple of other things but nothing changed. He said I could send the tester in to make sure it's good. Meanwhile I found a borg warner module that tested good, but car still runs the same. The parts store is going to replace my module tomorrow. I might need to start a new thread, but wanted to update. I wonder if I have a cam or valve issue.

 

[SloGN]

Update on my original post. New fuel pump cured the backfiring and popping. Now it just doesn't pull like it used to. I kind of sounds like a big truck when they put on their jake brake. I have a caspers ignition tester to check the module and coil. The old module showed bad and the used one that I got from someone on here. So I go to town and buy a new ac delco ignition module and it test bad the exact same way as the others. The guy at caspers had me check a couple of other things but nothing changed. He said I could send the tester in to make sure it's good. Meanwhile I found a borg warner module that tested good, but car still runs the same. The parts store is going to replace my module tomorrow. I might need to start a new thread, but wanted to update. I wonder if I have a cam or valve issue.

If the new fuel pump cured the backfiring and popping my bet is that your headgaskets are on the way out. I just recently lost a set of head gaskets due to a walbro failure and it ran lean and popped a few times and then the car just didn't run right. I keep messing with it until i noticed that i was getting small tiny air bubbles in the overflow tank and then i knew what i was chasing a leaking headgasket when under boost.

 

[gndrager]

after i fixed my fuel pump and poping issue i checked my push rods and 3 were bent

 

[Mike70gtx]

After a few of my bigger pops, I started getting a loud ticking in the valve train. But next day it would be gone. It comes back every now and then. I guess I'm going to have to pull the valve covers.

 

[Quick6'n'-K.C.]

vacuum hose at charcoal cannister or egr split or fallen off?

BW

 

[Mike70gtx]

Brian, were you referring to my situation. If so, I have had the charcoal canister removed. How do I check egr?

 

[Jerryl]

Update on my original post. New fuel pump cured the backfiring and popping. Now it just doesn't pull like it used to. I kind of sounds like a big truck when they put on their jake brake. I have a caspers ignition tester to check the module and coil. The old module showed bad and the used one that I got from someone on here. So I go to town and buy a new ac delco ignition module and it test bad the exact same way as the others. The guy at caspers had me check a couple of other things but nothing changed. He said I could send the tester in to make sure it's good. Meanwhile I found a borg warner module that tested good, but car still runs the same. The parts store is going to replace my module tomorrow. I might need to start a new thread, but wanted to update. I wonder if I have a cam or valve issue.

Reply from the "other thread"
Make sure you FP goes up 1:1 (+1 psi fuel pressure for each 1 psi boost)
So, if static is 43 psi, you run 20 psi boost, you should see 63 psi fuel pressure.

 

[Mike70gtx]

With vacuum off I'm at 43. I put vacuum back on I'm 38 or so. WOT goes into high 50's (57, 58)

 

[GNVYUS 1]

What brand is the new pump?

Sounds like you're seeing 1:1 now which is great.

Most likely you lifted a head, a lot of us Hysterical Weakbro owners lifted a head due to the F pumps being lame ducks out the gate.

 

[Beamer]

With vacuum off I'm at 43. I put vacuum back on I'm 38 or so. WOT goes into high 50's (57, 58)

What boost are you running? If only 15 lbs, then it sounds fine. If you are running 20 - 22, then it is not good.

Mike

 

[Mike70gtx]

24 pounds. I'm putting on a another new ingnition module today and I will get some better readings.

 

[Beamer]

24 pounds. I'm putting on a another new ingnition module today and I will get some better readings.

I think you still have a fuel problem. Possibly a regulator issue.

Any other inputs out there with this?

I was pushing 23 - 24 lbs at the track earlier this month and think that my 58 lbs fuel pressure was a sure problem. My 55# injectors were running at 90% plus duty cycle to try to keep up with my lack of pressure. I had been fighting a lean problem on my WB for a while and just realized about this walbroke problem. I just hope that when I get my new Denso, that everything else is OK.

What O2 numbers are you running?

 

[Mike70gtx]

My o2's and air fuel looked a little rich. I am shooting dual nozzle alky (denatured).

 

[Beamer]

Definately keep us posted with your info and results. By the way, where did you get the pump from? And what model is it?

Thanks,
Mike

 

[Jerryl]

24 pounds. ..........

With vacuum off I'm at 43. I put vacuum back on I'm 38 or so. WOT goes into high 50's (57, 58)

I think you still have a fuel problem. ...........

X2
43 static pressure + 24 psi boost = 67 PSI fuel pressure
Dual alky will cover up a few "sins of the fuel system" , but not all of them, and, it most likely saved your HG/motor. (another fine example of alky)

Get the gage verified for accuracy, make sure there are no leaks in the FPR boost signal line, voltage is good, etc.