Well, I am in need of some ideas to try and move forward.

Started this build during winter and finally got the motor in the car a few months ago. '98 TA with an iron 408 in it now, all forged guts, 248-254 629-613 114LSA

Car ran perfect on the first startup and started the break in and had 30 miles on it before I had a noise in the top end that came and went. Sounded like a lifter, but I found nothing definitive. They were LS7 lifters so I pulled them all and went to a Lunati high rpm link bar setup. While the heads were off I noticed a few valves had minimal wear so I sent them to the machine shop and all the intake guides were replaced, valve job, and milled .002 since they got a scratch there.

So this made me re-check the valve wipe, which required the rockers to be re-shimmed, which led to new pushrods. So I upgraded to 11/32 heat treated Mantons. Measured pushrod length many times and added the correct preload and had them made. Checked them when they arrived and they were right on spec so finally put it all back together Sunday.

I pre-lubed the motor and made sure oil was making it through every rocker, then buttoned it up and turned the key. Fired up and the valvetrain was louder then I remembered, but after it warmed up it quieted down a lot. Can barely hear the valves closing anymore.

Ran it again today and it ran good. Put 40 more miles on it and then it started to bog down a lot. I would not go past 3k, exhaust got crazy loud, and you could put it to the floor and it would not get the rpm up any higher than 3k.

It used to idle at 1100, then it started acting goofy and changed idle to 900, then a few seconds later 700, then down to 500 (sounded good, but not a good rpm for this car) I got it to the front of my driveway and put it in reverse and it just died in the road. Tried to fire it up and it just sounded like a garbage disposal. So I had to get a rope and drag it out of the street with my mower.

Pulled the valve covers and no broken rockers. Turns over with a wrench. Started sounded like it wasn't engaging with the flexplate, just freewheeling, so I went under the car and the starter would not retract from the flexplate. Had to pound the wheel out of the flexplate. Bolts were still tight, so I pulled it and threw on a car starter that I had.

Now I can crank the car, but it won't start. Cranked it with the throttle body all the way open and you can hear it popping and puffing out the exhaust and the intake. When I would let off the key a few times is sounded like it wanted to try something for a split second but no.

Sounds like when I was setting timing on a bbc and didn't have the distributor turned correctly. Timing chain only had 6k on it, cam degreed perfectly. Doesn't make sense that it would suddenly just start losing power over a 5 minute span until nothing. Great oil pressure and voltage. Fresh 93 octane gas, coolant looked new so no blown head gasket. Still need to drain the oil and look for a surprise.

I was varying rpm up to 4k, babied it and put a load on it like you should with breaking it in. Correct oil. Had enough of a tune to break the motor in. Mostly stayed in the 14's on my wideband, then with a load into the 12's. Occasionally would hit 16 for a few seconds at idle then go back where it should. Never overheated, cannot find any burned wires. No DTC's. Timing chain isn't snapped since I can rock the flexplate back an forth a bit and feel the small amount of timing chain slack that should be there. Verified this by checking my stock 6.0 in my work truck.

Cam position sensor maybe? Ran good at first, the only thing changed was that small amount of valvetrain work, changed from a pcv setup to breathers and that's it. And it ran fine after that for 40 miles, then turned into nothing. Only thing good was that possible lifter noise that I was trying to get rid of was gone. I guess I went too far and eliminated all noises.

Looking for any ideas. Probably going to have my tuner scan the car and see if he notices anything that I don't see.

Thank You

-mark jr.

 

All the usual things. Check compression. Check spark. Check voltage at the fuel rail and fuel pressure.

The starter issue... That usually occurs in engines with too much timing, or main or rod bearings toasted. For your case I'm hoping the latter is not the issue.

I hate to jump straight to the worst case scenario. In my experience it's usually something simple and could very well be a defective cam position sensor. But, before you go throwing part$ at it, at least do a compression check and verify the other basics are good. Inspect the plugs and their gaps while they're out for any inconsistencies/irregularities.

 

Very possible you have a reluctor wheel problem, hate to say it. Quick way to check is bring number one cylinder up to TDC take marker and mark the balancer and frt engine cover. Then take a timing light and crank the engine over and see if its close.

 

Originally when the crank was shipped to me, the reluctor wheel was bent and needed replaced. The engine shop I used had the degreeing tool, and I verified that it was installed properly, That I know for sure.

I drained the oil and it was perfectly clean along with the drain plug.

Pulled all plugs and cylinder 1 and 8 were the blackest, the rest were lighter and close to being equal in color. I expect them to be dirty due to not being fully tuned yet.

Fuel pressure was 60psi at the fuel rail

disconnected coil pack harnesses, fuel injectors and pulled the pump relay and started checking compression. reaked like fuel, but that was probably from trying to fire it last night. cylinders 1,3,5,7 all were at 175-180. My gauge wouldn't hold the number so it may be leaking, or that may be how it works, but they were all equal in everything. I will check the other side tomorrow, then start looking at fuses and wiring, then I am not exactly sure yet.

 

Have you checked for any DTC's? Your CKP might have went out or if the wiring harness was too close to the headers/exhaust it could have melted some wires. When you are trying to start it does the tach move and show engine RPM?

Also does your car have a MAF?

You said the car hasn't been "fully tuned yet" Are you running a mail order tune?

 

It very well could have flooded. Not sure that solves the overall mystery. Good news so far on the compression and debris free oil.

One thing I always check are electrical connections. Especially grounds and battery terminals. With EFI, sensor grounds to the block/heads are good to double check too, especially on a somewhat fresh build.

I learned my lesson on loose connections for the last time when I wasted an entire day of engine dyno time chasing down a stumble/glitch that only occurred at 6000rpm. I checked EVERYTHING. Even tested continuity in every wire in the EFI loom, even replaced the entire harness. Turned out to be... simply, a loose battery terminal that, at 6000 rpm would vibrate at a certain resonance and would start interrupting power. Never crossed my mind to double check it because you could look down at it and plainly see it was connected, the starter had no problem starting the engine, and the volt gauge read good.

Point of the story is connections that aren't tight can do different things at different temperatures and such. And... check the ones that you think "obviously" (for whatever reason you believe it to be obvious) don't need to be checked. And check them with your hands not your eyes.

I hate to have you checking every little thing, but it's part of the game, and much better than throwing money/parts at it. Same **** I'd be doing if it were me. And ultimately, it's just the right way to track something like this down.

 

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Tonight I plan on checking the other cylinders for compression and start going over the wiring harness. When I was putting this together I made a point to move wiring as far away from heat sources as possible and made custom brackets to do so, but, I will check again.

No dtc's showed up and yes it has a maf. I have a few 85mm ones around so no problem swapping those. Not sure what you mean by CKP, sounds like crankshaft relearn procedure, but wil check into that.

No mail order tune here. It was the original tune from my 5.7, had a friend change cylinder volume since its a 408, and input the new injector data since these are resized injectors

 

The reluctor has probably moved.....check it like I mentioned above.

 

If the reluctor moved, that ends this car till spring since I will be too busy with work, and this gets stored in a car hauler, so no room and way to cold to do anything. That is the worst outcome.

I guess I should be able to pull the starter and the crank position sensor and shine a light through the hole to see if it looks like it moved

 

Once all the basics are verified, it's absolutely worth checking the reluctor. I'm not keenly aware of the process of replacing one or how likely they are to move once replaced, but I'd certainly verify it. Especially since we know it has previously been repaired.

As you mentioned, it's fairly simple. One step I'd personally add to the procedure you outlined, is to remove the fuel pump fuse and relieve any fuel pressure from the rail by depressing the Schrader valve on the fuel rail, while holding a rag around it to soak up any released fuel (protects your eyes too).

I'm not sure what factory timing is while cranking (anyone know offhand?), but I'd assume +/- 10º BTDC. The TDC reference mark drawn on the dampener should be within an inch or so and to the left of it's original position (referenced to the matching mark drawn on the timing chain cover) once cranking and viewed with a timing light.

BlackDuk98, if your issue hasn't been resolved and it comes to checking this and you need instruction on accurately marking TDC on the dampener... let me know.

 

CKP-crankshaft sensor. It controls the injectors, timing and several other things.

The relearn procedure should have been done after you put the engine in the car and let it get to operating temp.

I do not know the long term effects(if any)of not doing a crank relearn procedure.

From how you described the problem I would look closely at the CKP and MAF. Keep us updated!

 

I don't think so............its not that simple in the car. Timing light will tell you in a few seconds. Do it so you can move on.

 

Can't say I have ever seen any timing marks on a stock balancer. I will look at it tonight and see what it shows while cranking.

 

Someone else here had the same problem. The plugs were swapped out for new ones and it did the same thing it drove for a while and then fowled the plugs. U might just need a tune.

 

I pulled the plugs and they were just soot covered black, Some more than others. The car should run on these plugs since I have pulled way worse plugs from cars that seemed to run fine, but its definitely worth a try. Even in lawn equipment that people abuse, the plugs I have seen that you need a screwdriver to chip the carbon off that still ran is amazing. It is worth trying for sure.

I am working on figuring out using a timing light while cranking it over with no timing marks

 

Thank you all for your suggestions for figuring this car out. I was going to set timing, so I looked at the balancer for a mark which I realized before I crawled under my car that it wouldn't be there. No place to draw marks on the cover, and I would have to tear the front accessories and water pump off to even aim the timing light at the balancer.

So I decided to do a quick and easy check like I mentioned before. Pull the starter and the crank position sensor and shine a light and mirror and see if it moved. Couldn't see anything so I stuck my finger in there and tried to push it in the direction of the back and front of the car and it was solid. So I used my finger nail and for the hell of it tried to spin it. Guess what... ****** spins on the crank with minimal effort. So it probly messed up the mounting surface for the reluctor wheel on the crank. Took me 8 months to get it to this point. So it is done for the year. Going to start ripping it apart so it can get taken care of over winter. Missed an entire car season. tons of late hours and draggin myself to work just to get to enjoy the car for a month before it goes into storage all for nothing.

 

Man that sucks. I was really hoping it was something easy. I know your pain of getting your build done only to have something to go wrong that wasn't your fault. However thank you for updating your thread, it very well could help someone out.

 

I tried to tell you this from the start, your symptom's were spot on. To use a timing light just bring number 1 cylinder to tdc then just take a marker and mark the balancer and cover ANYPLACE you can see it. THERE ARE NO FACTORY MARKS ON ANYTHING. You are going to create the marks on THE BALANCER AND ENGINE. Any place you can see them, with the engine at number 1 TDC it doesn't matter where you mark it as long as the mark you make on the balancer matches the mark on the engine.

I'm guessing you think you need factory marks or a timing plate? YOU DON"T. Or you don't understand how to find TDC on number one?

 

I understand all of that, it just wasn't registering in my brain at the time. Before I crawled under the car it dawned on me how to do that. I will make sure to mark everything when I put it back together this winter.

Thanks for the help