TBI Question

Blueleader · Oct 15, 2006

If you don't want to run an EGR valve, you really need to disable it in the calibration for things to work right. If you just disconnect it, you'll get detonation. Exhaust gasses displace oxygen in the mixture so the ECM cuts fuel to compensate when it commands EGR flow. If the exhaust gasses aren't there because the EGR valve is in a garbage can somewhere, the oxygen isn't displaced but the fuel is still cut, causing a lean condition and knocking.

Which ECM do you have? If it's a 1227747 (common on '87-'92 trucks) , I can burn you a new prom with EGR (or anything else) disabled. Even if it's a different number, I still might be able to work with it.

Edit: I almost forgot, the exhaust gasses make the mixture burn slower so the ECM advances the timing a bit during EGR operation to compensate. That's also part of the whole knocking thing. No exhaust gasses in the mix, no slower burn.

Blueleader · Oct 15, 2006

crash said:
Be ready to get a stock tbi intake..

Played that game before :;
(Don't be shocked when you have goofy idle surging)

Yeah, mine did all sorts of bad things with the stock prom. Actually it was barely drivable. The first couple prom burns cleared up most of it.

Without any tuning, you definately want to keep everything as close to a stock TBI 350 as possible. Especially the cam.

Binder · Oct 15, 2006

Mine seems to run good though I haven't driven it yet. Kinda concerned that I only have 9 PSI fuel at idle. Is there a adjustment on the fuel reg?

crash2 · Oct 16, 2006

Binder said:
Mine seems to run good though I haven't driven it yet. Kinda concerned that I only have 9 PSI fuel at idle. Is there a adjustment on the fuel reg?

No adjustment on the regulator unless you remove the top part of the tbi, and drill out the welded screw for the regulator. can you pinch off the return line and get the pressure to go higher? If not your pump is not doing its job..

Binder · Oct 16, 2006

It's not the pump. This pump made 18PSI with the old TB. I think I'm going to run it as is and see how it performs. If not good I'll take the reg apart to adjust it.

crash2 · Oct 16, 2006

Binder said:
It's not the pump. This pump made 18PSI with the old TB. I think I'm going to run it as is and see how it performs. If not good I'll take the reg apart to adjust it.

Or just buy a new regulator....:;

Binder · Oct 16, 2006

Yeah I thought about that too. $65 for the adjustable TBI reg or add a reg to the return. We'll see how it goes.

Jay W · Oct 16, 2006

Rick, it's easy to adjust the stock one once you get it apart and look at it. When mine was having low fuel pressure problems it would run good until I floored it under load. Then it would cut out. It turned out to be my pump.

binderbound · Oct 17, 2006

Make sure you have an aldl plug. Buy a aldl cord off eBay so you can hook your laptop up and log data. Download Winaldl, its free.

Running a 1bbl TBI from a fireo, astro harness, truck computer(7747). Tps, iac, temp, o2, are all I run. With the aldl info my buddy burned a perfect chip for my 4cyl IH. I love it. Best thing I ever did for the scout.

CrustyJeep · Oct 17, 2006

Who has a picture of the ALDL plug? I can't find mine.......... I have the wires to it all seperated and labeled, but nowhere to put them.

SnoFalls · Oct 17, 2006

CrustyJeep said:
Who has a picture of the ALDL plug? I can't find mine.......... I have the wires to it all seperated and labeled, but nowhere to put them.

Are you just looking to cable it to a laptop? Here's the ALDL pinout ...

If it was me, I'd just cut and wire a serial (or USB) pre-built cable to the wires you have labeld ... (you *could* build your own, but that is more trouble than worth IMO).

CrustyJeep · Oct 17, 2006

Hmm that's way more wires than I've got... What year is that diagram from?

SnoFalls · Oct 17, 2006

That's *the* OBD-1 ALDL plug ...

it's only 8 wires total :flipoff:

seriously, you only need the A, B, E, M pins to mate the cable ...

this link has probably the best circuit BTW ...

CrustyJeep · Oct 17, 2006

Ah OK... I only have four I think (plus the ground)

crash2 · Oct 17, 2006

yOU guys make this sound so complicated

All you need on the ALDL is pin A(ground) pin B(diagnostic test) and pin M(serial data)

binderbound · Oct 17, 2006

Really you dont need the 'B' either.

Read to your hearts content http://www.binderbulletin.org/forums/showthread.php?t=47254

Remember, its for IH's so disregard the distributor conversion. If you cant figure it out from that link, you need to hand in your keys and drive a yugo.

crash2 · Oct 17, 2006

binderbound said:
Really you dont need the 'B' either.

Read to your hearts content http://www.binderbulletin.org/forums/showthread.php?t=47254

Remember, its for IH's so disregard the distributor conversion. If you cant figure it out from that link, you need to hand in your keys and drive a yugo.

Its alot easier to flash code with B there though...

binderbound · Oct 17, 2006

yes, but he didnt want to run a check engine light. plus, with Winaldl you have all the data in real time. No need for codes, it flags whats wrong. you just have to keep your laptop handy. The way my system has been, once I got the bugs worked out it has been a 'turn the key and forget about it' deal.

crash2 · Oct 17, 2006

binderbound said:
yes, but he didnt want to run a check engine light. plus, with Winaldl you have all the data in real time. No need for codes, it flags whats wrong. you just have to keep your laptop handy. The way my system has been, once I got the bugs worked out it has been a 'turn the key and forget about it' deal.

Whats the baud rate on that setup? I know the old tech 1 was like 9600 and the tech 2 is almost 20k. It might be "real time" but if its slow it cab some times do you no good.

But why complicate matters. How many will bring there laptop on a run? I sure in the heck won't. I had one instance going up isabel. The rig started dieing and hard to start. I flash coded it and found a problem with the temp sensor and was able to make a temp fix. All becuse of a simple check engine lamp and A/B terminals...

binderbound · Oct 17, 2006

9600 sounds about right. Mine runs so good that I havent had to log data in forever

My laptop was free so i dont worry about bringing it on runs. I carry 1 of all my sensors and a spare ECM. They were all leftovers from junkyard scrounging. Problem with these conversions is sometimes you get a code 12 constantly or random codes cuz stuff isnt exactly factory. Especially when things start getting deleted out of the chip. Its just annoying having a blinking light on your dash, IMO.

edit- i guess you wouldnt need to hook the light up. just have it on hand. Also, you need your laminate of what all the codes mean.