New issue just popped up. Any further idea's?

cbshea13 wrote:

phantom 309 wrote:

So the opti was degenerating over a few hours?



??

I'm not sure how I'd put this.  It seemed to start right up after *fuel pump swap, spark plug swap...etc*  but then eventually start to have the issue.  (I think this is how I'd put it anyway, from what I saw/heard Tim say.  (I was there doing the fuel pump swap one day, and it fired right up after the fuel pump change - only to go back to the problem later in the day.)

Note:  On Monday it started hard again for him, but I don't know if that was before or after the Opti change (I was at work and could not respond to his text, but according to post he changed it Sunday night)

Edit:  had to change use of > making my text not appear lol.

Not exactly Chris. For months I have had an issue with long cranking (2-3 seconds maybe) and I have been putting it off. The latest issue started when the long crank became a no start, at least no start until messing with it for 1/2 or so. This was after sitting for 2+ hours.

The fuel pressure presented itself as low based on the GM FSM. I went through 3 Fuel Pressure Regulators to finally get one close to spec. This made little to no change (I don't believe that was an issue at all). Chris and I pulled out the fuel pump and looked it over blew into it and it seemed to be fine. Put new plugs in when I had the headers off prior to doing the opti - no change. I never swapped the fuel pump. The Opti replacement seems to have solved the long crank issue , when it starts it starts quickly. I still seem to have an issue that lets me sit after 2+ hours. It requires 30+ seconds of total cranking to get it running. The new issue is the started just clicking when it is cold for the first key turn or two. I think this is a failing starter.

The good news is that MSD is rebuilding the Opti for me so I have a spare.

bad battery connection at the starter,.

Yeah Nick I was thinking the same thing. On the road. First thing I am going to check when I get home.

phantom 309 wrote:

bad battery connection at the starter,.

I double checked this today. My "Gary's" wires are all nice and tight at all points.

BigBlackBeaSSt wrote:

phantom 309 wrote:

bad battery connection at the starter,.

I double checked this today.  My "Gary's" wires are all nice and tight at all points.

Nice and tight doesn't guarantee 'good' at the starter

phantom 309 wrote:

BigBlackBeaSSt wrote:

phantom 309 wrote:

bad battery connection at the starter,.

I double checked this today.  My "Gary's" wires are all nice and tight at all points.

Nice and tight doesn't guarantee 'good' at the starter

explain please

1. Any stored codes?
2. Do you have access to a scan tool?
3. Do you have a FSM?
4. Do you have a fuel pressure gauge?
5. Do you have a spark tester?
6. Do you have access to a set of noid lights?

There are a few things that will cause a hard start. The one that leaps to mind is the engine temperature -- computer may think the engine is cold. Even though you may have replaced the sensor, the wiring may be the issue. You could meter the temperature sensor probe from the PCM to verify the total resistance is correct for the actual temperature. Similarly, if the TPS circuit is returning a high voltage, the PCM may be entering "flood clear" mode -- normally triggered by pushing on the gas pedal when cranking, the PCM shuts down the injectors.

The FSM has a section on hard/no start conditions. One thing they mention is the MAF can be installed backwards, causing a rich condition. The car should fall back if the MAF is unplugged, so in the absence of a scan tool, that might be another diagnostic you could try.

Verifying the presence of fuel pressure and spark might help isolate the condition. I know you've done a lot of parts swapping in that regard, but it's always worth double checking, especially when swapping in used parts. Noid lights are used to confirm that the injectors are getting some sort of voltage.

buickwagon wrote:

1. Any stored codes?
2. Do you have access to a scan tool?
3. Do you have a FSM?
4. Do you have a fuel pressure gauge?
5. Do you have a spark tester?
6. Do you have access to a set of noid lights?

There are a few things that will cause a hard start. The one that leaps to mind is the engine temperature -- computer may think the engine is cold. Even though you may have replaced the sensor, the wiring may be the issue. You could meter the temperature sensor probe from the PCM to verify the total resistance is correct for the actual temperature. Similarly, if the TPS circuit is returning a high voltage, the PCM may be entering "flood clear" mode -- normally triggered by pushing on the gas pedal when cranking, the PCM shuts down the injectors.

The FSM has a section on hard/no start conditions. One thing they mention is the MAF can be installed backwards, causing a rich condition. The car should fall back if the MAF is unplugged, so in the absence of a scan tool, that might be another diagnostic you could try.

Verifying the presence of fuel pressure and spark might help isolate the condition. I know you've done a lot of parts swapping in that regard, but it's always worth double checking, especially when swapping in used parts. Noid lights are used to confirm that the injectors are getting some sort of voltage.

1. Any stored codes? No light, although I have not hooked my computer to the car (between laptops)
2. Do you have access to a scan tool? Tuner CATS
3. Do you have a FSM? Yes
4. Do you have a fuel pressure gauge? Installed on the fuel rail
5. Do you have a spark tester? No
6. Do you have access to a set of noid lights? I buddy is trying to find his for me.

About an hour later

interesting how the tach doesn't even twitch while its cranking,..

The Click sounds as a starter motor beginning to fail, but than it cranks just fine. (I had the same problem with the click, up to the point there was no start at all. replaced the starter, solved the problem)
Can't help you with the other problem. Yours is a 94 LT1, mine a 93 TBI, no clues here

BigBlackBeaSSt wrote:

1. Any stored codes?  No light, although I have not hooked my computer to the car (between laptops)

Of particular interest here would be DTC 16, 18, 41 or 42. If one of those sets, the light does NOT come on and the injectors will be shut down. Code 16 indicates a loss of the low resolution pulse from the opti -- bad sensor, dirty ring, wiring, PCM failure, etc. Was your replacement opti new or used? Any chance something is getting heat-soaked and failing when hot?

Code 18 is an injector circuit electrical fault -- driver, injector, wiring, PCM, etc.

DTC 41 and 42 is the Ignition Control circuit, and 41 will ONLY set during cranking. Possible causes include the module itself, PCM, and of course the wiring/connectors.

There are a number of other codes that can be set without turning on the light, but most of them deal with the transmission or AC and I'm not aware of any that would prevent starting.

It would be nice to confirm the presence or absence of a code before wasting any more time and effort. If you can't get your scan tool program going, you should at least check through the CC system. You do have the FSM so I won't bother repeating the diagnostic chart steps here.

Quote :

2. Do you have access to a scan tool?  Tuner CATS

I've never used that. Does it have the capability to monitor the live data? The live data stream tells you what the PCM is actually seeing on each circuit. EG: what the PCM thinks the engine temperature or barometric pressure is, how many volts it is seeing from the TPS, etc. and some of the outputs too. If you see the PCM is commanding an injector pulse width of 0, then you know a lack of fuel is deliberate rather than an injector wiring problem. If you have an understanding of the system, the data stream can point out problems that are not yet severe enough to trigger a code, especially on circuits that are normally variable. For example, I once had a no-start problem because the ECU thought the engine was at was 20°C when in reality it was -20°C outside. -20° is a valid temperature, so it won't trigger a code, but it made a huge difference in the amount of fuel supplied.

Quote :

5. Do you have a spark tester?   No

A cheap, effective and safe way to test for the presence of spark. Get one.

Quote :

6. Do you have access to a set of noid lights?  I buddy is trying to find his for me.

Another thought is to try a shot of starter spray or propane from an unlit propane torch in the intake while an assistant cranks the car over. Potentially dangerous, so wear eye protection, gloves and stand to one side, but if the car tries to fire it suggests a fuel problem. Could be too rich or too lean, as ether and propane both have a wider explosive range than gasoline, but usually means lack of fuel. Especially if one of the above codes are set.

buickwagon wrote:

Was your replacement opti new or used? Any chance something is getting heat-soaked and failing when hot?

It was a new Opti and yes a real chance of something (what I dont know) getting heat soaked. Initially it acted up after it was sitting for 3 hours or so and also cold. Now cold it seems to start fine, but when it gets 2/3rds of the way warmed up it does not want to start.

Oh and I do have a spark tester and just bought the NOID test set at Advanced. No testing tonight, but I might get a chance to work it tomorrow in the PM.

So just before WagonFest Virginia, Mr. Mike Hanlon spent the better part of the day working on the beast with the noid lights and spark tested. When it would not start the noid lights and spark tester were going off and it would not start.

Today is the first chance I have had to do much else. I swapped the injectors for another set in had in the drawer. I will need to some time to test run it to see if there is any change. Going to Rochester over Thanksgiving week, hope to have it to take and drag bambi home with.

BigBlackBeaSSt wrote:

So just before WagonFest Virginia, Mr. Mike Hanlon spent the better part of the day working on the beast with the noid lights and spark tested.  When it would not start the noid lights and spark tester were going off and it would not start.

Today is the first chance I have had to do much else.  I swapped the injectors for another set in had in the drawer.  I will need to some time to test run it to see if there is any change.  Going to Rochester over Thanksgiving week, hope to have it to take and drag bambi home with.

Interesting,. has spark,. has injector pulse,. but won't start,.

Did you try the foot to the floor while cranking,.?

So in my saga to find the issue I swapped out the injectors to my old injectors, I pulled the tank again to fix the fuel gauge I messed up last time I had it down and also straighten out the o-ring that seem to be leaking some fumes on a full tank. No change.

The FSM mentioned that the MAP sensor is part of the the start up sequence for the motor. So on a whim, and since I had a extra in the drawer, I swapped it. I do not like the factory seal they have on that sensor, they all seem to look cockeyed to me. The rubber seal on one I took off was not in great shape. Well I have run the car all week, started in most all scenarios very well. So I think that was it. Seems to be running rich when cold, but I think that is by design, but time for a little data logging to see if anything can be improved.

I know I have said fixed before so I hope this time it truly is.

On a side note I just ordered the HD fuel pump harness from Racetronix. They are typically difficult to deal with, they do not even publish a phone number. I bought it from Tick Performance out of NC as they were a bit friendlier. I want to do this upgrade anyway.