1SLwLS1

iTrader: (6)

Yea so priorities have been shifted recently and this car still isn't running right, haha. I work 7 days a week and when I get home, I have absolutely zero motivation to do anything other than R&R.

Back around mid October, the car started to hiccup very hard around 2-2.5K and would temporarily lose the tach signal to the dash. About 20-30 seconds later, it would come back up and drive normal. So, I replaced the camshaft position sensor and that hiccup went away and it was back to the 4-4.5K breakup.

I finally replaced the coils last weekend and switched to AC Delco truck wires and that didn't fix it so I sold those last week and went back to stock length AC Delco wires. I had actually planned on ordering new injectors this week just so I could have a spare set. If the injectors are the issue, I got around 1 year of good service before they went to crap and since this is my DD, I figured having a second set that I could rotate yearly without having to pay big $$$ for overnight shipping to get them serviced and begging for rides, it just makes more sense to buy a new set for backup.

When I was about to order the injectors, I had an idea that was much easier and cheaper to test. The PCV system on these cars suck and the dual catch cans I bought didn't do crap (Saikou Michi) and the intake had a nice coat of oil. I figured well maybe the oil is fouling the plugs and they can't hang at the 4K frequency so I removed the PCV system last night, put on a couple breather filters, removed and cleaned the intake as well as swapped to a new set of TR6's. Well, that didn't fix it either.

I went to test it last night and it broke up pretty bad with black smoke pouring out the tail pipes so I drove around for a bit thinking the intake cleaner and what not still needed to be removed from the CC. I tested it again and it was a little better later in the evening but it was 3 AM and the cops were looking for drunks so I just parked it. This morning on the way to work, I went WOT and it broke up as bad as before and I lost my tach signal again. WTF?? I replaced the friggin camshaft position sensor a little over a month ago and now that gremlin is back.

I am about at a total loss. I am going to order a set of injectors in the next week or two, swap the fuel filter tonight, and if that doesn't work then I am going to swap to a Racetronix fuel pump with hot wire kit. After that, I have no clue. That is absolutely everything needed for proper combustion; suck, bang, and blow. If fuel isn't the issue, PCM maybe?? Either way, I am going to have to drive to Victoria to have Pat G check it out or pay a local shop to diagnose it.

This car and I haven't seen 6K in months. It's friggin depressing...

****END RANT****

Sarg

iTrader: (6)

And no codes during all this?

1SLwLS1

iTrader: (6)

Not one. Although I am pretty sure its fuel related. I took the engine up to speed in 1st without WOT and it would hesitate but not as bad which points me to the direction that the fuel supply cannot keep up since the engine can rev this high with less load.

Sarg

iTrader: (6)

We had 2 cars with similar issues. I ended up being the fuel pump cutting out after getting too hot. We could reach down and feel the pump (external inline) was scalding hot and would drop fuel pressure. The other we were able to gap down the plugs to about 26 and it was cured. Seems like some serious electrical gremlins in your case from what you describe that appear when things get hot.

1SLwLS1

iTrader: (6)

I could see the fuel pump being the issue but it continues to maintain pressure which leads me to believe if its fuel related, its at the injectors. I just remembered that I wanted to add a larger ground. I have the larger truck alternator with a larger charge wire but ran out of fittings for the ground and finishing that up got lost in my personal chaos. I will get some fittings today and add an additional ground, I think that may be one issue with the electronics.

RWDCelicadude

I just read the whole thread and was wondering if you'd checked grounds. I would definitely add a ground or two and clean any related connectors. I would also track down the ecu ground and make sure that one is clean and tight. Poor grounds can cause all kinds of strange issues.

BlumaroZ28

This works about 95% of the time to narrow down source of a misfire...brake torque the car, you dont have to ripp the tires just load it up real good. if its a bad coil or wire it will typically fail under load. Also, if you have access to a lab scope you can check every sensor, the fuel pump and injectors electronically. if you dont have one then do some research and find a shop that uses a lab scope on a daily basis. ask them for print outs of the wave forms on each part you want checked. (we give them to our customers after every diag job we do) ohm test parts works sometimes but doing a current ramp test is much better becuse sometimes the windings in electronic devices will only break down under a load. trying to diag the problem first will save a lot of money and time just swapping parts, especially with parts of CL that you cant really be certain were good anyway. good luck intermitant problems suck! (sorry but i had an after thought. What are the actuall air temps outside as compared to your IAT temps. with the car running a while and it hot outside, its not unresonable to have IATs into the hundreds.

1SLwLS1

iTrader: (6)

After 162 days, after 23 weeks, after 5.5 months, it is finally fixed!! The problem boiled down to a couple of issues.

Luckily, I had a hard time believing the injectors/fuel system were the cause due to the intermittent failure and just the way it would occur.

Issue #1. This past Saturday, I finally got around to adding 10" of 2 gauge wire to the battery/chassis ground. When I was doing that, I noticed the battery was loose and attempted to tighten it. Ends up the battery tray was broken so I bought a new coolant reservoir/battery tray from the parts store and took it for a test drive. The hiccup was still there but ever so slight; the car would still accelerate past the hiccup and make it to 6,000 RPMs. I knew I was on the right track. The main issue was the fact that I have a long post for accessories and when the battery would rock back, it would short on the AC accumulator bracket.



Issue #2. That ended Saturday and I began work on Sunday. When I cleaned the intake and deleted the PCV system a few weeks ago, I noticed the intake manifold gasket and throttle body gasket were worthless. If I would have had alternate transportation, I would of replaced them while it was off but that was not feasible. So, I replaced those gaskets this past Sunday. I fired it up and the recent high idle (obvious vacuum leak) was solved as well but I couldn't take it for a test drive due to being blocked in my driveway. Plus, I needed to get under the car and clamp the hydraulic clutch cable off the collector as well as remove the aftermarket oil pressure sender so my aftermarket oil temperature sender could work accurately and didn't want the engine super hot for all of this.





Issue #3. While I was at it, I cleaned every ground I could find. I also noticed the bare ground strap that goes from the driver side block to the front frame rail was dangerously close to the alternator output cable. So I wrapped that up in electrical tape as well as cleaned all of the grounds. The only reason I did that is because of the large charge cable inhibits the protective boot from properly protecting the terminal. I have ordered a 1/0 gauge big 3 kit which should eliminate that issue entirely.

After that, I poked around the passenger side wiring to make sure none of those wires were burnt or corroded from the header and noticed the crankshaft position sensor wiring was really close to the header, it was between the starter and header. So, I decided to rearrange those wires and move that particular cluster between the starter and engine block. When I finished up with that, I went to fire it up and take it for a test drive as I was no longer blocked in my driveway. Well, it wouldn't fire and I drained my battery attempting to get it running. It was turning over without any signs of ignition. Every time I mess with the wiring on that side, it burns the crankshaft position sensor. I don't know why that is but I have a lifetime warranty on it as the OE sensor went out when I replaced my SB with a 408 over a year and a half ago.

Finally last night I replaced the sensor, and took it for a cool test drive. Success! I then decided to let it get hot so I could test it under all conditions. I drove around running some errands and letting the car idle the entire time; oil got up to 220F, water temperature up to 190-200F, and the alternator output down to around 13.5-14.0V. Once hot, I wound out 2nd, 3rd, and 4th gear in "Mexico" without one single hiccup! I drove it to work this morning getting nice and hot as well and again, no Hiccup! The engine hasn't seen 6500 RPM smoothly in over 23 weeks!!!

Thanks to everyone's input and help. I am glad my stubbornness to not rule out electrical gremlins paid off!

ducatisl

iTrader: (1)

Congratulations!

I had been following this thread for...23 weeks! It's amazing how electrical problems can really screw with us and it's usually the simple things or the basics such as bad grounds or shorts that are usually the culprit. The complicated answer is usually not the right answer.

1SLwLS1

iTrader: (6)

Yea, I couldn't believe it, it was definitely bitter sweet. After all the time and money wasted, it was something as simple as a broken battery mount and dirty grounds. I am just glad its fixed though.

I don't think the vacuum leak was an issue until recently as I removed it 3 times in the past 2 months, first to replace the camshaft position sensor, second to clean the intake and delete PCV, and third to replace the gaskets, much less probably 5-6 times before that with head swaps, OE oil pressure sender issues, engine swaps, etc.

RWDCelicadude

Glad to hear you got it sorted, that sounds like a royal pain but at least you can enjoy your car again!