CHRISPY

I have been having a hard start problem for quite a while. Need your opinions on what could be the cause. (I had it when my motor was stock and after my motor etc was put in as well.) Car otherwise drives perfect and runs awesome. Just takes a while to start when cranking.
Here is what I have thought of and checked so far:

clogged injectors (cleaned)

Bad plugs (changed)

clogged fuel filter (changed)

Bad MAF (changed)

burnt wires around starter (inspected it but couldnt see anything out of the ordinary)

What else could cause it? Bad MAP sensor? Fuse blown somewhere? Cold start fires right up most of the time. Occassionally it takes a bit of gas and a little cranking (10 seconds or so)

Anyone have any ideas?

Thanks in advance,
Chris

JS

iTrader: (4)

Fuel pump or relay poss. crapping out

JS

<small>[ October 25, 2002, 11:25 AM: Message edited by: JS ]</small>

Pro Stock John

iTrader: (34)

Bad MAF
Disconnected IAT
Burned Crank Position Sensor wire
Burned starter wires
Bad 02 sensors

JimmyKash

Do you have LS1Edit tuning? I bet you could fix it up in there.....this happened to me once in my old motor when i had DFI

With the stock computer the motor would like to crank a bit before starting...when i put the DFI in and before i even tuned it from the guy's other tune which was for a 400hp 383 and i had a 400hp blower car....the thing fired RIGHT UP.

So i bet it is in the tuning somewhere

AgaveCorvette

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Pro Stock John:
<strong>Bad MAF
Disconnected IAT
Burned Crank Position Sensor wire
Burned starter wires
Bad 02 sensors</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Bad O2 sensors won't cause a hard starting problem. The car starts in open loop.

cantdrv65

iTrader: (3)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by AgaveCorvette:
<strong> </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Pro Stock John:
<strong>Bad MAF
Disconnected IAT
Burned Crank Position Sensor wire
Burned starter wires
Bad 02 sensors</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Bad O2 sensors won't cause a hard starting problem. The car starts in open loop.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">If the car spins over well it's not the starter wires.... <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

MelloYellow

Starter?
Coil Packs?
Fuel Pump?

CHRISPY

I checked the car with ATAP and found I have a dead (low voltage) CMP sensor (Cam position sensor)
ARE had a couple lying around so I swapped it out in the parking lot and the problem still remains.

ATAP Also says I have a MAF low frequency code as well. But when I rev the car the MAF appears to be functioning normally. (Weird)
I swapped MAFs and the same problem.

Going to replace the crank position sensor tomorrow and maybe rewire the cam position sensor and MAF wires at the track. I'll get it figured out <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
Thanks again guys for the pointers!
Cheers,
Chris

AndUAndI

You're on the right track. Had similar problems with the LS1 I just dropped into a 94 Z28 chassis. From the GM manuals, and my time spent diagnosing, the diagnosis maps point to the following, in this order:

MAF disconnected or broke
Crank position sensor (my problem was continuity here)
Cam position sensor.

If you still have problems, take a few minutes to check the continuity of the wires with a meter. Also, if you have the pinout on the sensors, check the 5 volt reference from the PCM and the ground back to the PCM.

The crank position sensor wires are close to header primaries, so it is possible to damage them.

wrencher

iTrader: (2)

Fuel pump's internal 1 way check valve not holding fuel pressure engine off & bad commutator on pump motor causing poor fuel pressure cold.

JPR

It could be as simple as the IAC open or closed too much at cold start, re-check your counts hot. Another thing to check would be rail pressure from sitting overnight and how quick the rail pressure builds when turned to the "on" position in the morning. Dunno?

Joe.