Herper84

iTrader: (7)

I just got done installing heads. Now my car will run horribly for a second or two, backfire and just die. Both the IAT and the ECT read around -41F. I have tried swapping both sensors with known working ones. I have checked for ground/continuity in both the sensors and the ECM grounds. I have no DTC's present.
Anyone have any ideas?

01WS6/tamu

iTrader: (37)

Check the grounds on the back of the heads.

fuseone

did you have the negtive battery cable off for awhile?

01WS6/tamu

iTrader: (37)

did not matter if he did it still should not backfire and die.

Herper84

iTrader: (7)

I have a total of 3 individual wires that I have grounds to the back of the heads. I checked for continuity in all the ECM grounds. All of the ECM grounds are in fact grounded.

Yes, the (-) cable had been off for about 2 months.

TJ

iTrader: (10)

no professional here, but i would check pushrod length and cam/crank sensor AND wiring.

kjvail1204

heads, means intake came out, means distributor, maybe its 180* out....

Dskeet6

iTrader: (20)

put the wrong wire on the wrong plug????? maybe????? not calling you an idiot but i have def. seen people do it before

Herper84

iTrader: (7)

Car doesn't have a distributor, pushrods are 7.325 dead on the money (checked with a length checker), Plug wires were all labeled before being taken off so there is no way they are in the wrong sequence. There are no codes so it's not a misfire or a sensor being unplugged or a bad sensor. I ran the ECM with HP Tuners and all the sensors are within normal limits except for IAT and ECT. I'm at a loss here. I only took off the heads/intake. I didn't touch any of the timing components.

Keep the suggestions coming! I appreciate all the help!

kjvail1204

sorry still transing from the 88, i would jsut go over the wires again, jsut ot be sure, i mean it sounds like timing, thats the only other thing it oculd valve open when its suppose the closed, i am also thinking rocker arms, not tight enough, or over tight, so its not opening or staying open, again im just guessing havent had the pleasure of thanking my LS1 apart....YET

30th t/a

iTrader: (51)

crank sensor or crank sensor wires. I just went through this with my car. do a search on my name and with my thread. good luck

Herper84

iTrader: (7)

I can't even get the car to idle for more than a second or two. The ECT will dump fuel in the car if it's cold like -41F. My main concern is why both the IAT and ECT are reading all messed up.

King Nothing

iTrader: (9)

people forget a backfire can be caused by a vaccumm leak . . . are all your gaskets sealed correctly? did you sequence the bolts correctly? did you drag the ***-end of the manifold when you put it back on?

2001WS6Vert

Jumper the IAT/ECT connector and see if you get a high number. If so the sensors are bad, if not check for a 5 volt supply from one side of the connector. If no voltage ohm the wires from the connector to the ECM to check for an open/short.