popping

kevin

Member
Joined
Mar 16, 2002
hi,i was tuning on my 87 and when you give it a little gas off idle it has a dead spot and sometimes pops back through the air cleaner.what should i look for?thanks
 
i have no vacum leaks.also should the wastegate sylnoid click a few times when you first turn the key on? it started that now.
 
geez.i guess my prob. is so hard that nobody has any idea.i'll figure it out.thanks for nothing.
 
kevin, what injectors & chip are you running? Popping is usually ignition related, but what you're describing sounds more along the lines of a "tip in stumble". Does it only do this right off idle??
 
Hey Kev, B4 you "get your panties wrapped around the axle", how bout some more info??
1. Do you have a scan tool? Readings??
2. Just what does "tuning" mean? What did you do to the car?
3. Did the problem surface B4 or after the "tuneup"??
4. Has the car been subjected to the famous "spring cleaning" process?
5. What mods are in place?
A. Adj FPR?
B. Plugs and what gap? Plug wires?? New, old, etc?
C. Fuel pump and hotwire?
D. Electrical system mods such as volt booster?
6. What tools do you have to test with? Coil pak tester, VOM, GOOD fuel PSI ga., compression ga., ETC, ETC.
7. How many miles on the car?

Given the problem as described, is more than likely electrical, as already said, I'd do a MAF tap test, clean and tighten ALL grounds, clean and lube all connectors,sweep the TPS w/ the VOM to see if it has a bad winding, check alt output and battery volts w/ engine at idle.
Look to see that the POS cable has not gotten into contact w/ the DP. [Could be a bad motor mount]
You can OHM the coilpak.. Best method is the tester from Caspers!!

I doubt the boost solenoid would make the car act as you described. I believe the cliking is the ECm verifying the presence of the sol. on startup.??
Has the cam sensor been out of the engine? Is it loose?
Has the crank sensor been checked for proper air gap and being secure in the mount? While you are there, check to see if the balancer is loose.
Once all this is done, get back to us and let us know what you've found.
:cool:
 
ok i got my panties un twisted.the car has 110,000 miles.new timing chain valve springs,36#inj.49 turbo,maf reading is 6 at idle 240 at wot.02's are 790 at wot with 40# static.new ac 43's gapped at 35.new wires new ign mod. and coil pack.i will check all the stuff you mentioned.when you go wot the car hesitates then goes but feels like it is bogging.thrasher 92 chip.90 octane and i'm running 16# of boost with 1 degree of knock.i welded my header a couple months ago and put a tie down on.sometimes the car will not spool up when foot braking.the 02 says 850 when i foot brake.sorry i came off harsh and thanks for your help.
 
???

Kevin, the 90 octane, and the timing in the chip, plus 16# of boost could trigger the knock retard enough to cause the "bogging" feeling. What kind of scan is the 1* showing on?? If it's off the ALDL, you may not have a refresh rate fast enough to catch it all B4 the retard goes into action.
You can try the following.
1. Add some Zylene to the gas tank.
2. Turn the boost down to about 14.
3. Add a couple # of FP. [Do the Thrasher directions call for 45# static??]
Only 240 MAF at WOT sounds low. You should be able to peg it at 255. Any chip gurus have any input on this??
Is the O2 sensor fresh? Is it a DELCO??
Does the chip have a BLM lock patch in it?
850 on launch w/ footbrake is kinda rich.. It may cause the sluggish feel til the boost catches up and the A/F gets down in the 700's.
Do the rest of the tests and let us know what you find.

Chuck
 
i turned the fuel press. down because i was running rich.i have the scan master in the computer plug.i just went out and drove it and i think its my 02. idle is ruff now and when i went to drive it my 02's go down to 100 if you give it any gas.its a standard brand 02.it isnt giving a code.chacked fuel press. and its ok.the 02 is a week old but now i remember that i ran some 110 in it.
 
O2?

Kevin, I'd change the O2 to a AC Delco, put the FP back up to the 40's and try it again. the Scanmaster is a good tool, but relys on the slow refresh rate of the data stream from the ALDl. Know anyone that would loan you a Directscan?? That would give you ALOT more data in a short time period.
Do you have an aftermkt DP on the car? If so, is the puck sealed on the exh.hsg?? Has the hsg been ported to the max for the size of the puck?
Do you have an aftermkt bleeder valve on the boost control?
 
i have the stock down pipe and no bleeder valve and no enlargement on the puck.thanks again and i'll post back when i put a new 02 in.i dont know anyone with a direct scan.
 
Are the injectors Real blue tops or 868? If 868 have a chip burned for them. you are asking for problems if you try to run a Thrasher. Definately run 45 psi with a thrasher and I wouldn't try 90 octane and 16 psi of boost with 40 psi FP. The pop was likely a lean pop if that were the case.
 
thet are the ford blue top's.i put in a new ac 02 and prob. went away.i turned the fuel back up to 45.90 octane is the best we can get around here.i have an alky kit but the pump locked up.i put a dump on it tonight and i can tell a big diff.i turned the boost down to 14 and it has no knock.i'll be getting race fuel this weekend.thanks
 
like chuck said run a 70% gas 30% zylene?????? (xylene)we won't count off for spelling. It should bring your octane rating to arround 97,combined with alky you should be rockin. also should be able to turn boost back up.
 
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