Problems on startup!!!!!!

[gradon]

Look over on bratcop's project build to find the article.pdf to properly sync the cam sensor(.http://motorage.search-autoparts.com/mo ... rticle.pdf) It'll also show how the guy used a dual trace o-scope to view the cam and crank signals simultaneously and how after the toothpick method, the signals were synced. A drb from the dealer will also show if the signals are synced. Throw in the various variances: a harmonic balancer thats a degree or so off, a timing set a lil off, #1 not fully ATDC@0*, an aftermarket cam w/ a dizzy gear that doesn't mesh like the stock did(so dizzy tab needs to be cut), and things'll be off. I would like to use a dual-trace o-scope or drb someday so that I can know that they are sync'd.

[crustodd2]

Thanks Graydon,
I'm back to the stock cam, but my mechanic keeps leanin' in the direction of the problem bein' there, so we'll check out this info.

[crustodd2]

UuuuuGH! Still strugglin'. Finally got the engine off of running lean. Put new 24# cobra injectors in, same as the one that were in there, then it went to seemingly running rich. Had the UniChip tech come down and update the software and try to road tune it. The A/F ratios are spot on in closed loop.

Here's the symptoms:
*Starts hard-Turns over fine, but it's stumbley to catch fire. Once it has been running, then it starts up more normally unless it sets for a little while. Could this be my EXPENSIVE Hesco FPR leaking down? Fuel rail pressure only measured 37 psi?

* Driving down the road-Idles great, but feels SLIGHTLY like it's missing off and on at moderate road speed. Good response up to about half throttle, then if I step hard in to it or even from a dead stop WOT, it starts to buck and backfire and fall on it's face. We thought the exhaust might be plugged. It's not. Replaced the coil. Still does it.

What to look at??? TPS? PLugs?? They're new. Plug wires? 15K old. It NEVER ran like this with the old stroker. It was obviously bad when the cam went, but it was only slightly sputtery at almost redline before and that was finally tuned out. I'm HATIN' this and the cost is getting BIG. I'm wishin' I'd done a 5.3 Chevy transplant at this point! It would have been cheaper.

[4.whoa]

Could this be my EXPENSIVE Hesco FPR leaking down? Fuel rail pressure only measured 37 psi?

Is 37# all you can get -max? If so I'd change the fuel filter and check that the lines didn't get dented and that your connections are good to the pump.(elec) It shouldn't be from leaking down,since the pump primes the system as soon as you turn the key.
Next time you try it,turn the key to run,NOT start listen for the pump to prime and stop. turn the key off then to run again to "pump up" the system. My '95 will usually do this twice, but once in a blue moon three x's. Then see if it will start easier.

[YJason]

Can a 6 cyl run 180* out of time? I had a SBC one time that had some similar symptoms like you explain and it was running 180* out.

[yuppiexj]

Have you indexed the distributor?
http://www.angelfire.com/my/fan/dist_index.html

[crustodd2]

Yes the dizzy has been indexed, the fuel filter was replaced and the bag/screen on the fuel pump pickup was cleaned or replaced. I'm gonna pull the plugs and check them tomorrow. Too much gap? Also could it be plug wires? The really bad symptoms have come up rather spontaneously. It did not run like this when the cam was goin' bad. I can't figure out what would have occurred in 2-3 months of it sittin' that would be makin' this stuff happen.

[crustodd2]

OK, so I had a chance to drive around a bit today. I turned the key on to the on position and made sure the pump is coming on. Check that. It still starts hard, lots of turnover, but it didn't really fire up until I pushed down on the throttle?? Strange for fuel injection. When I went driving around, it runs relatively normal at in-town speeds. Up to half throttle and 3000-ish rpms, it's pretty good. Snappy off idle, smooth idle too. The stock cam and springs are WAAAAAY quieter than the Lunati was. The new eutectic pistons are also MUCH quieter than the old 944's. When I stomp the throttle from a dead stop or even at road speed, 30-40 mph, it REALLY stumbles and misses at about 3000 rpms. If I go in to the throttle gradually, it's not so pronounced. Does this sound like a TPS issue? CPS maybe? The hard starting is less after it has run, then is shut off, then restarted right away. Come on people, someone has had these symptoms before. HELP

[SilverXJ]

Refresh my memory. What happened to the original KB 944 build? Something about too much clearance or gas contamination?

How far do you press the gas pedal to get it to start? Usually when you floor the pedal it cuts the injector signal, which is a method to clear a flooded condition.

I've had hard starting with a faulty CPS. You can test the TPS with a volt meter.

[xj2588]

have you cleaned your IAC?

[crustodd2]

Hey Silver,
I will go out to run an errand in a few mins and check the pedal movement. The 944 build ate the cam, and lightly scored a couple pistons. I rebuilt using stock cam and springs, 4.2 rods and the KB eutectic pistons with more dishing. SCR is about 9.0:1 now with a .063 quench, not perfect, but better than stock. The IAC should be clean, but I can go through the list as folks will suggest options. Member IH392 is about an hour from me and I may need to take it to him. I hope he reads this. He has 30 yrs experience and should know the situation better than anyone else I can find around here. Other than the minor internal changes, there hasn't been anything drastic that should be fouling the works like this. As I have mentioned, it ran normally as the cam was goin'. Smooth and consistent right through the rpm range.

[crustodd2]

Ok, just went out for a short drive. Same erratic start, and it just needed a blip of the throttle and it fired up. This was totally cold. It won't rev past about 2200 rpms without missing in our out of gear when cold. So this would be an OPEN LOOP condition??? I f I push the throttle down easy and no too far, it will rev pretty normally up to 4000+, and that seem to be under load and when it's warm. So it's in CLOSED LOOP in this situation??? If I go past about 1/3 throttle it starts to buck and miss. Again rolling down the road or parked, same symptoms. Also, it is running a bit warm 220-ish. The cooling system is fairly new too. Hi flow water pump, T-stat, and T-stat housing, stock radiator, fan clutch, and heater core all in the last 20K or so.

Whatcha' folks thinkin'?

[FOXxX]

I am interested in your situation because I am having an identical - well exact to be exact - problem as you. Irratic starts, some more so than others. Having to bleep the throttle to get'er running. Idles great and runs a little on the warm side. Closed loop runs like a top but open loop is more spurattic. I've done everything up to degreeing the cam as far as timing, coil replaced, Cam sensor replaced, Fuel pressure reg replaced, spark plugs re-gapped, and I am fixin to change my CAT thinking it is clogged. At night does your headers glow at idle (I can only see it at night).

A question I have since I haven't verified the CAM degree, will the motor run if the CAM is off by a tooth? Can it be off by less than a tooth? How would your exhaust affect this issue?

[crustodd2]

Hey Jeepers,
PROBLEM SOLVED Thanks to all that have responded. To those still strugglin' with issues, listen to the "senior" or SMARTER members. They're USUALLY correct. IT WAS THE TIMING!!! The dizzy was not correctly indexed, though I'd thought it was. The tech/tuner, Shelby Johnson of Johnson Engine Service in Salem Oregon, methodically went through all of the systems with some sort of digital scope and other "modern" equipment. I humbly admit this stuff is beyond my full understanding. Can someone do a comprehensive "laymans" writeup on the A/F and Timing. He finally concluded it was a timing issue, cut the tabs of the bottom of the dizzy, made the adjustment, locked it back down with a GM retaining tab, and AWAAAAAAY WE GO! Now, as most of you who have read this know, the UniChip work was done WROOOOONG! Shelby said the the A/F's are all over the place and it needs to be remapped. I think I should be refunded from UniChip for the shoddy work AND actually have it done right. It probably cost me $250.00+ in transportation, time off work, and fuel to have the incorrect stuff done so far. I think the "Chip" is a decent product, but poor service so far. What do you guys think?

T~

[92tank]

well im glad you got it running right but how do you expect UNI to get the afr right if the thing is not running right in the first place