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Unread 02-17-2013, 10:33 PM   #16
motormike24
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Quote:
Originally Posted by budblind View Post
Your best bet is to go over to the IH forum, Binderplanet.com and look at the injection tech section. The moderator, BillUSN1 is a wealth of knowledge in regards to TBI conversions, and doesn't give us Jeep guys too much ribbing...

To even to begin to troubleshoot your warm start problem, I think you need to monitor the SES light from connector pins A6 to A5. If you don't have the ALDL connector at least jumper pins A9 to A12 to put in diagnostic mode to see whats going on.
OBD1 systems don't need a lot of fancy diagnostic tools, mostly a good multi meter and knowing how to use it. God bless.
Jon In Tucson
not sure if it matters for your idea, but its a cold start problem, not warm. starts great when its warm, not when its 25 degrees.

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Unread 02-18-2013, 04:09 AM   #17
86cj74.2L
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I would want to see what temps the PCM thinks its seeing. Both engine temp and intake / throttle body temp. Sometimes the throttle body temp is used to calculate its warm start parameters. If their not within 10 degrees of each other and within 10 degrees of ambient temps they need replaced.

You have power at ignition on to the injectors, and what not? Reason I ask is because there is a feed circuit in that engine bay that only gets power after the engine is running. It's off the oil pressure switch.
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Unread 02-18-2013, 09:41 AM   #18
motormike24
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Originally Posted by 86cj74.2L View Post
I would want to see what temps the PCM thinks its seeing. Both engine temp and intake / throttle body temp. Sometimes the throttle body temp is used to calculate its warm start parameters. If their not within 10 degrees of each other and within 10 degrees of ambient temps they need replaced.

You have power at ignition on to the injectors, and what not? Reason I ask is because there is a feed circuit in that engine bay that only gets power after the engine is running. It's off the oil pressure switch.
i will check for power during "key on" to inejectors, but id have to assume it does since it will pulse injectors just fine to start up when warm. i dont see how temp would affect the power from ecm to injectors. as far as the circuit u referred to from the oil pressure switch, where does that run to, as my GM ecm is not tied into the oil pressure switch at all as of now. its a one wire sending unit, so im assuming that runs directly to the factory oil gauge, right? and if it IS supposed to be connected to my new ecm somehow, why was it starting in all temp ranges with no problem before i swapped the distributor, but not after? im still stuck on that part. because if i understand the gm system correctly, the ecm uses the signal from the coil primaries to pulse the injectors, right? if thats the case, im thinking there must be an issue that is related to that but im still confused at why it would be affected by temp. today is my last day in town at my buddies place so it'd be really cool if i could get this figured out, lol. thanks.
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Unread 02-18-2013, 01:13 PM   #19
86cj74.2L
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You need a manual to see where the wires are. There are some in PDF format here somewhere.

They fed the electric choke and the intake heater and were on the oil switch to ensure their we're only energized after the engine was running.
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Unread 02-18-2013, 02:16 PM   #20
86cj74.2L
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The temp sensors are used to determine which fuel map to use during a start condition. As an example.

There are a few scanners out there that will read OBD1 as well as software to load on your laptop. Running fuel injection without being able to see what it's seeing and having access to the trouble codes makes it awfully hard to figure out what's wrong.
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Unread 02-18-2013, 03:29 PM   #21
motormike24
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Originally Posted by 86cj74.2L View Post
You need a manual to see where the wires are. There are some in PDF format here somewhere.

They fed the electric choke and the intake heater and were on the oil switch to ensure their we're only energized after the engine was running.
but wouldnt that all be run from the stock jeep computer? i followed several write ups for doing the ecm wire harness, and i dont recall reading anything that said to tie the GM ecm into the oil pressure switch... someone suggested that maybe part of the GM ignition module is fried?
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Unread 02-18-2013, 04:00 PM   #22
CSP
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There is no stock Jeep computer. A pressure switch relies on oil pressure to be built before the switch closes and contact is made. This technology pre-dates computers being used. I'm not sure what power feed is being referred to, but that's how it works.
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Unread 02-18-2013, 05:02 PM   #23
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I was wondering if he accidentally grabbed one of those #10 or #12 wires from the oil pressure switch for power because they are there. And would have no power Untill the engines running.

That's all.........
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Unread 02-18-2013, 05:07 PM   #24
motormike24
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There is no stock Jeep computer. A pressure switch relies on oil pressure to be built before the switch closes and contact is made. This technology pre-dates computers being used. I'm not sure what power feed is being referred to, but that's how it works.

there IS a stock jeep computer. thats what ran the original carter carb that was on it, as well as the intake heater, o2 sensor, distributor, etc. otherwise there would be no way to control spark without points. also, if there was no stock computer, how would the nutter bypass have come about? not trying to be an ***, just saying there IS a computer because i relocated it to the drivers fenderwell. also did the nutter bypass. but currently i have both the GM ignition module AND the factory ECM hooked to the coil primary wires (positive and negative feeds). maybe thats part of my issue?
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Unread 02-19-2013, 07:42 AM   #25
gmakra
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Here is my thought, it possible you messed up the wiring but then again you may have something else going on also.
So go here and down load WINADL http://winaldl.joby.se/
Make a cable or buy one and see what the computer says is going on.
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Unread 02-19-2013, 08:55 AM   #26
CSP
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The point you blew right over is that the stock computer, which you've removed 99% of what it did by removing the feedback carb, had nothing to do with a pressure switch activating circuits.

BTW, the ignition module controls spark. Every CJ from '78 through the 90 YJ has the same one and pre-81 CJ's didn't have any kind of computer.
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Unread 02-19-2013, 04:26 PM   #27
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well here's an update. On a far fetched hunch, i was prompted by several people to replace the GM ingition module that i had spliced into the whole TBI rig. i figured, if that was bad i'd have to lose spark. i mean, after all, isnt spark the entire job of that module in this particular setup? but, i had great spark, right on time. however, since my last post, i had put a timing light on the crank, and found that the ignition timing was 15 degrees too early. so i adjusted the distributor, and set timing to 10 degrees BTDC. seemed to run much better, my lack of torque past 2000 rpm seemed to mostly go away, but still had the slightly off beat idle (almost like it was still out of time). still wouldnt start when cold. not one drop came out of the injectors upon cold crank. so i bought another ignition module (new), and hooked it up. boom fired right up, BUT the temp was already 130 degrees. so not guaranteed that fixed it. most of the time, even at full operating temp, it would crank 6 or 8 times be4 firing. this time, it barely cranked twice and fired. so i let it get cold again. cranked and cranked, no fire. so i pulled the air cleaner, and loah and behold the throttle plates were soaked. definately had fuel this time. sprayed starting fluid in case it wasnt enough fuel getting to the cylinders. still no fire. so held it at wide open throttle, and after 4 or 5 cranks it roared to life, but wouldnt hold an idle unless i kept my foot slightly on the gas for 15 seconds. then it would idle. but it runs like crap when cold but kinda ok when its hot. so im thinkin i fixed the no fuel during crank problem, but now maybe the distibutor needs to be re-timed? what do you guys think?
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Unread 02-20-2013, 09:52 AM   #28
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so, last night, before i had a chance to bring the jeep in the garage to mess with the timing some more, i had another car i needed parts for. the jeep wouldnt start, with fluid or otherwise, however it seems that it was spraying fuel during cold start, FINALLY. however, i lost all spark. this was AFTER i replaced the GM ignition module. i still had the old one mounted to the body, and had the new one taped to the top of it til i could get it in the garage and properly mount the new one. so, just tryin to figure out why the hell i lost spark in less than an hour after installing the new module, i hooked the old crappy one back up. it fired up immediately. ran like crap, but at least it ran. i barely made it to the store and back, stalled several times. i understand new parts can be defective, but jeez, is there something that could possibly be killing these modules??? help please!
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Unread 02-20-2013, 12:30 PM   #29
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Borq Warner and Motorcraft i believe are the best ones.All the knockoffs are junk.So its not uncommon to get more than one that fails
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Unread 02-22-2013, 10:21 AM   #30
motormike24
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Borq Warner and Motorcraft i believe are the best ones.All the knockoffs are junk.So its not uncommon to get more than one that fails
i got the BWD brand (borq warner), and now it starts, but im back to square one. still only sends fuel warm. is there a way that maybe i can completely run the spark and fuel control from the GM computer, without needing the factory jeep computer hooked up via the nutter bypass? it seems i remember at one point trying to do that, but as soon as i clipped the wires comming from the jeep computer, it wouldnt run anymore. maybe not, idk. im just so frustrated with this seemingly simple design. and ive tried unplugging temp sensors, and pluggin em in again, nothin seems to affect this issue. except temperature.
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