Hello everyone! I picked up an '87 from a buddy with too many projects on his hands, and I'm very new to the L98.

So, it looks like he:

Replaced the smog pump with the idler pulley set up. All the cats are gone.
Replaced the EGR stuff and starting injector with block off plates.
He had 42lbs injectors in it, but I replaced them with 22lbs.
He put a wideband sensor in it. It's sitting around 14, but the plugs keep looking like they are fouling.
He replaced the chip with a Bluetooth chip emulator. I looked at the tune in it, and I tried doing some research on which
base tune to start with, i.e. smog, EGR and startup injector delete etc., but I'm really unfamiliar with the OBD1 setup.

I'm 99% sure the timing is off. I unplugged "the plug you're suppose to unplug to check the timing", but I couldn't get a
timing mark to show up. Either the timing is way off, the balancer spun or my timing light is bad.

The throttle body has a new IAC and TPS, but the big "vacuum" port (not the water port, which is blocked off)
is not connected, blocked off, but not connected to anything. The little port on the bottom is attached a vacuum hose tee.

So...that's just about everything I can think of. Any suggestions on where to start?

Any help would be greatly appreciated an thanks in advance!

Kevin

 

Timing is the first thing to start with. Assuming the plug wires are good and not crosswired.

Once you start messing with the tune though you can have anything. Why did he have 42lb/hr injectors on it in the first place?

 

I don't think he researched it very well and bought the first set of injectors for a "C4" he saw.

And I will double check my wires, firing order and TDC. Any idea where that big vacuum port on the throttle body should be connected?

A diagram on another post says CCV on the pass. vavle cover. Is that really just it?

 

Depending on how they replumbed it after the emissions stuff was removed, it is either the CCV(air in) vent line or goes down to the purge solenoid.

 

Cool. Thanks for info and advice! Let me double check this stuff. Then I'll have to dive into the computer stuff.

 

Can you be more descriptive than "Poo Poo" on how it's running? Is it stalling, studdering under acceleration, feels low on power (have you ever driven a TPI C4 before as they aren't exactly fast to start with), smoke out the pipes, over heating (what temps), etc?

If he put 42lbs injectors on the car it would have needed a tune or he dropped the fuel pressure a lot. Since you mentioned it had that tuner on it I'd assume it was tuned for those injectors. I'd strongly suggest:
- Make sure the fuel pressure is set correctly for the car.
- Get a stock chip (or tune) and start there. The EGR, cold start and air pump wouldn't make the car run bad when removed even using a stock tune. All but the cold start is very common for people on stock tunes. The cold start removal wont effect how it runs once started.
- Get the engine to TDC on the compression stroke and see where the timing mark is located. You should be able to see it easily at this point. If you need help with this I find it easiest to just pull the plug from the #1 cylinder, plug the hole with my thumb and rotate the engine with a breaker bar. You'll feel the pressure on your thumb when you get on the compression stroke. Timing may be off but I can't imagine it's off enough to where the timing mark isn't visible when running. If so, you'd have a hard time getting it to idle properly.
- Make sure there aren't any vacuum leaks. The place under the TB being plugged isn't a problem. Hook up a gauge if you have one (cheap at harbor freight if not) and see what it reads at idle.


Once we know more, we may be able to help better.

 

You're right. I shoulda put a little more info on how it's actually running! Alright, here goes:

Haven't got to drive it yet. No overheating. First TPI.
I got it from my buddy "running" barely, way rich.
I swapped out the 42lbs-ers for the 22s, and replaced the fuel pressure regulator diaphragm, which took care of the richness.
He told me he never got around to actual tuning, but did load in the driver for the emulator and a generic base tune.
I'll do a little research and see what's loaded in there. He did give me the Hypertech PN: 127072 chip that someone had put in there at one time. I'll put that back in to see if that helps.
It starts, but doesn't idle (really feels like a vacuum leak). That's why I was inquiring about throttle body ports and block off plates and such to make sure I didn't have something plumbed wrong. Other than that, I'm not seeing any obvious leaks.
Some blowby coming out of the valve cover vent (157,000 miles and been sitting a couple years).
I double checked that the #1 cylinder is at TDC, and the timing mark is lined up properly to the 0 on the indicator. The rotor is pointing at the #1 plug wire.

I do need a vacuum gauge to check that. And I do have a new timing light so i can hopefully get a good number to see where the timing is at. I'm looking for 12 BTC at idle with the little plug unplugged and in gear, correct?

Thanks again!

 

On an 85 it's 6 degrees of base timing. I'd assume the same on 87 but can't confirm.

Where are you at? If in the North Austin area I'd be willing to help or lend you the tool/gauges. I'm up in Leander.

Sounds like timinh should at least be close. TPI's can be a PITA will manifold/runner vacuum leaks. But it would normally take a pretty big one to make it not run. I have a smoke machine that works wonders on finding them though.

Try the chip you got. My gut is telling me the tuner is at least part of the problem too.

 

Thanks for the help offer. I am in Phoenix, AZ,

 

Well everyone, I've had a significant set back. I got the fuel rail and intake back on after the new 22lbs injectors. Double checked the basic timing position of everything. Dumped 5 gal. of gas in it. Hooked the battery up. Gave it quick crank to check for fuel leaks and the injectors from cylinders 6 & 8 sprayed fuel like there were no o-ring in them, turns out they got pushed too far up into the rail. All I can come up with is there there must have been a bad plug wire or something, but I now have a little fire damage on the pass. side of the engine compartment. Nothing too, too bad, melted injectors and connectors, melted vacuum hoses on the plenum, even the main wire harness and distributor got a little melted, not so bad they're unusable, but not good to look at.

So being that it's a L98 with 158,000 miles on it...you know where in going with this...yep, LS swap time. I know, controversial topic for some, but I have a LM4 (that's the all aluminum 5.3) that has a little Magnuson 122 supercharger and a 4L60E that was putting 500 HP to the wheels in my 2004 Chevy SSR sitting around, so I might as well give it a new home.

Thanks again for all your help and advise. I think we were heading in the right direction.

I'm sure I'll be back looking for advice on issues that'll pop up with the swap, but I'll start a new thread for that.