Steve78LT

New to fuel injection, and could use some advice.

Thanks to some helpful members, I now know I have a '90-'91 TPI setup (Speed Density with $8d mask id) on a ZZ4 crate 350 short block. The motor runs fine when running but starts awful. There's a loud metal-to-metal clanking after a few normal cranks, which to me sounds like the motor kicking back from the initial timing being too advanced. Once it catches though, it purrs.

But I don't know how to set the initial timing. Or what to even set it to. The GM spec sheet for the ZZ4 says initial timing should be 8* BTDC, but I'm pretty sure that's for a carburated application.

I think the right setting is 0. I think I need to disconnect a connector right by my ECM (because it has a tag on it saying so). But that's about it. The ZZ4 has the distributor on the back of the motor (not an poti-spark style), so I presume I can put a dial-back timing light on the balancer and turn the distributor like any other motor I've had.

Can anybody point me in the right direction?

ninetyone

iTrader: (2)

it sounds to me like it is your flexplate hitting your starter. may need to shim the starter. If you are using the tpi style distributor,which i assume you are,then set the timing just like a tpi car. What timing cover and balancer are you using?

ninetyone

iTrader: (2)

need more info. What car is this in? Stock harness? Zz4 balancer and timing cover? Do you have a knock sensor?

Steve78LT

To me it does sound like starter-to-flexplate contact, but I don't think it's shimming because the noise isn't constant. I'll get 5-10 normal cranks before the clanking. The starter is new (that was the first thing I tried. It made the same noise with the old starter.

I'm not sure what a TPI distributor is exactly. Mine sits on the back of the motor and looks like a small cap HEI, but without the interal coil. There is a separate coil-looking thing on the passenger side of the motor. The coil, cap and rotor are all brand new. The distributor was on the motor when I got it. The GM paperwork says the distributor shaft needs a melonized gear for the cam in it, so I presume it has that. Is that what you mean by a TPI distributor?

Distributor ans coil

The timing cover and balancer are the ones that came on the crate motor (I believe). The ZZ4 has a roller cam, and the timing cover is a typical looking cover with the words "replace assembly after opening" or something like that (hard to read it behind the water pump).

Balancer (viewed from below)

ninetyone

iTrader: (2)

Yeah that is what i meant by tpi distributor.

Steve78LT

The motor is in a 1940 Ford streetrod. The harness is not stock - I believe its a Painless harness. It dos have a knock sensor, and we've swapped that out with a known good sensor to rule that out.

Also swapped O2 sensor, coil, rotor, did a compression test, swapped the starter, checked all the wires.

ninetyone

iTrader: (2)

So you are using the 1227730 ecm for speed density cars (1990-92) right. Just make sure you have the EST connector and if you do,then disconnect it and set the timing like you would any normal tpi car.https://www.thirdgen.org/settingtiming

Steve78LT

AWESOME LINK - thanks a million. I did search the board and FAQs, but didn't come up with this. Seems to be exactly what I need (I hope anyway). You guys on this board rock. If anybody ends up with a second gen, come on over to www.nastyz28.com - I hope I can help you out one day.