OBD1 ECU problems
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From: the Evergreen state
OBD1 ECU problems
i have a 1990 base civic hatch, D15B1 block, D16Z6 Head, intake and distributor, D15B2 water pump, D16Z6 belt, and an OBD1 ECU jumper. I’ve checked jumper harness from end to end with a PM6 and a P28 Pinot diagram, and pin-to-pin, all wires connect to the proper pins, I have a BRAND NEW HA MOTORS chipped ECU, tunes specifically for my NEW RDX 750cc injectors.
i just replaced the main relay. It didn’t click, pump didn’t prime, bench tested with a multimeter and found one of the circuits to be non-functioning.
Still no click and no prime. I have power at the B1 connection from the factory harness, but all wires on A, B, and C from factory harness are dead. Nothing. No power. None whatsoever coming out of the ECU from plugs A,B, or D.
the O2 and Vtec wires were added via the jumper harness, but otherwise (except for the 2 wires moved and 2 added for the MPFI Swap I did in 2015, which ran for 2 years) NOTHING ELSE HAS BEEN CHANGED.
i just replaced the main relay. It didn’t click, pump didn’t prime, bench tested with a multimeter and found one of the circuits to be non-functioning.
Still no click and no prime. I have power at the B1 connection from the factory harness, but all wires on A, B, and C from factory harness are dead. Nothing. No power. None whatsoever coming out of the ECU from plugs A,B, or D.
the O2 and Vtec wires were added via the jumper harness, but otherwise (except for the 2 wires moved and 2 added for the MPFI Swap I did in 2015, which ran for 2 years) NOTHING ELSE HAS BEEN CHANGED.
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From: the Evergreen state
Re: OBD1 ECU problems
It did before I switched main relays, after I switched the relay I found my battery was dead. Charged it enough to power the dash and ECU to check for power and test the relay, didn’t get as far as cranking yet. Figured if the ECU is not sending power out on any circuit there wasn’t any point in trying to start, seeing as there’s no O2, TPS, MAP, ECT, Air temp, injector, or main relay power.
Again, there IS power at the hazard fuse wire going into the ECU.
Again, there IS power at the hazard fuse wire going into the ECU.
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From: the Evergreen state
Re: OBD1 ECU problems
Sure enough, 10A fuse 14 was toast. Put a new one in and it fired right up. However it also immediately dies every time it starts. (Which at the moment isn’t ENTIRELY bad, because I’m in the process of addressing belt walk as well)
EFB055
Joined: Dec 2005
Posts: 13,249
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From: Brisvegas, QLD, Australia
Re: OBD1 ECU problems
Seeing that you're running 750cc injectors, i'm going to assume you're running a high flow fuel pump. If you check the spec sheet you'll probably find that the amp draw will be close to, or actually exceeds 10A. Try using the current fuel pump power wire as a signal on a relay, and run a separate fused power wire that the pump can draw power from.
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Thread Starter
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From: the Evergreen state
Re: OBD1 ECU problems
Seeing that you're running 750cc injectors, i'm going to assume you're running a high flow fuel pump. If you check the spec sheet you'll probably find that the amp draw will be close to, or actually exceeds 10A. Try using the current fuel pump power wire as a signal on a relay, and run a separate fused power wire that the pump can draw power from.
Everything ive discovered so far in searching that resembles my current dilemma leads to a faulty ignition switch not engaging the “run” selection only after returning from “start”, which from the number of posts ive read, seems to be a somewhat common and spontaneous occurance, similar to the ICM failure.
EFB055
Joined: Dec 2005
Posts: 13,249
Likes: 14
From: Brisvegas, QLD, Australia
Re: OBD1 ECU problems
Well injectors rated at 750cc/min*4 are going to outpace the factory fuel pump (236cc/min). It's possible to run big injectors on the factory fuel pump, but the people who say they run fine also probably don't have a setup that needs big injectors.
Everything ive discovered so far in searching that resembles my current dilemma leads to a faulty ignition switch not engaging the “run” selection only after returning from “start”, which from the number of posts ive read, seems to be a somewhat common and spontaneous occurance, similar to the ICM failure.
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From: the Evergreen state
Re: OBD1 ECU problems
I wasn’t saying that faulty switch blows the fuse, I meant that From what I’ve read, that the main cause I’ve seen in forums for a 1second fire and stall, such as I’m having now, was a spontaneous failure of the ignition switch.
it could very well be a fuel issue. It’s got a 79-ish lph pump. But then the question is, would a 190 be sufficient or would I need the 255? If need be I can look for a 550-ish injector set. This is NA and the 750’s were the only set available at the time for less than 400$ unless I got a used “as-is” set off eBay.
it could very well be a fuel issue. It’s got a 79-ish lph pump. But then the question is, would a 190 be sufficient or would I need the 255? If need be I can look for a 550-ish injector set. This is NA and the 750’s were the only set available at the time for less than 400$ unless I got a used “as-is” set off eBay.
EFB055
Joined: Dec 2005
Posts: 13,249
Likes: 14
From: Brisvegas, QLD, Australia
Re: OBD1 ECU problems
I wasn’t saying that faulty switch blows the fuse, I meant that From what I’ve read, that the main cause I’ve seen in forums for a 1second fire and stall, such as I’m having now, was a spontaneous failure of the ignition switch.
it could very well be a fuel issue. It’s got a 79-ish lph pump. But then the question is, would a 190 be sufficient or would I need the 255? If need be I can look for a 550-ish injector set. This is NA and the 750’s were the only set available at the time for less than 400$ unless I got a used “as-is” set off eBay.
it could very well be a fuel issue. It’s got a 79-ish lph pump. But then the question is, would a 190 be sufficient or would I need the 255? If need be I can look for a 550-ish injector set. This is NA and the 750’s were the only set available at the time for less than 400$ unless I got a used “as-is” set off eBay.
If you can estimate how much power you think you'll be making, there's a bunch of calculators online to help spec fuel injector and fuel pump sizing. Your setup is an NA D series right? why do you think the motor is going to need any more fuel than the OEM injectors couldn't give?
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From: the Evergreen state
Re: OBD1 ECU problems
After replacing the fuse, it will fire and stall WOTHOUT blowing the fuse. It will repeatedly fire and stall and every time after, the fuse looks fine.
I had wired in the D16Z6 distributor and attempted to fire it up to no avail, checked the wiring, noticed the timing belt was walking, and having to do brakes and oil changes on the rest of the family vehicles, pushed the car out of the garage for a while. In the mean time we had plenty of snow and rain and when we pushed it back into the garage, the main relay was bad, later discovered the blown fuse, and the drop-down pocket to the left of the steering wheel full of water. Turns out the door wasn’t shut all the way.
Replaced the fuse fuse and the car started 2nd crank and died. Turn the key off and back on, starts 2nd crank and dies.
since then I can repeat that process continuously until the battery dies. Every time I check the fuse, fuse is still good.
But it if you leave the key in the on position after it dies and keep cranking, it won’t ever start. You have to turn it off then back on then it starts in 2 cranks
I had wired in the D16Z6 distributor and attempted to fire it up to no avail, checked the wiring, noticed the timing belt was walking, and having to do brakes and oil changes on the rest of the family vehicles, pushed the car out of the garage for a while. In the mean time we had plenty of snow and rain and when we pushed it back into the garage, the main relay was bad, later discovered the blown fuse, and the drop-down pocket to the left of the steering wheel full of water. Turns out the door wasn’t shut all the way.
Replaced the fuse fuse and the car started 2nd crank and died. Turn the key off and back on, starts 2nd crank and dies.
since then I can repeat that process continuously until the battery dies. Every time I check the fuse, fuse is still good.
But it if you leave the key in the on position after it dies and keep cranking, it won’t ever start. You have to turn it off then back on then it starts in 2 cranks
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From: the Evergreen state
Re: OBD1 ECU problems
Update, belt walk has been solved. Somehow the guide washer which had been sitting inside the crank pulley on the floor with the shaft key not only failed to be installed, but has also completely disappeared. Tore the garage apart looking for it only to settle on getting one from picknpull.
Checked my wiring again, checked my fuse box, no blown fuses, but still have to re-prime the fuel system every single time it dies before it will start again. Continuous cranking will resolve in an intermittent splitter as if it’s TRYING to start, but no fire.
So Next step would indeed be pump and FPR? Correct me if my formula is inaccurate, but I’m getting 79,000cc/h or 79l/h out of my pump, but my injectors are 750cc/min x4 (3,000cc/min) x60=180,000cc/h or 180l/h. If that is correct, would the 190l/h suffice? (which I’m finding rather difficult to find, everyone seems to have 255 and 342l/h pumps) or as far as duty cycle should I just spring for the 255? Price is comparable between the two.
Checked my wiring again, checked my fuse box, no blown fuses, but still have to re-prime the fuel system every single time it dies before it will start again. Continuous cranking will resolve in an intermittent splitter as if it’s TRYING to start, but no fire.
So Next step would indeed be pump and FPR? Correct me if my formula is inaccurate, but I’m getting 79,000cc/h or 79l/h out of my pump, but my injectors are 750cc/min x4 (3,000cc/min) x60=180,000cc/h or 180l/h. If that is correct, would the 190l/h suffice? (which I’m finding rather difficult to find, everyone seems to have 255 and 342l/h pumps) or as far as duty cycle should I just spring for the 255? Price is comparable between the two.
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Re: OBD1 ECU problems
It could be the basemap. There is a good chance whoever made it only changed the injector size and didnt put the injector deadtimes in for those injectors, or it could be a million other things.
If you were not aware, youre going to need a real tune to get that thing to run with those injectors. Its not at easy as it is with small injectors.
If you were not aware, youre going to need a real tune to get that thing to run with those injectors. Its not at easy as it is with small injectors.
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From: the Evergreen state
Re: OBD1 ECU problems
Fully aware that it will need a live tune one the Dyno, ECU was bought chipped and programmed from HA motor sports, who SUPPOSEDLY, if you buy an ECU with a programmed chip, will create a BASIC base map based on a long list of components and parameters options and then test it before shipping.
(Vtec/no VTEC, launch control/no launch, no O2, VX/EF single wire O2, 4wire o2, 4 wire with single secondary, knock sensor/no knock, choose block generation and size, choose Vtec engagement or let them figure out where smoothest engagement is achieved, injector manufacturer and size, etc)
so if that is correct, then theoretically it should at least run.
(Vtec/no VTEC, launch control/no launch, no O2, VX/EF single wire O2, 4wire o2, 4 wire with single secondary, knock sensor/no knock, choose block generation and size, choose Vtec engagement or let them figure out where smoothest engagement is achieved, injector manufacturer and size, etc)
so if that is correct, then theoretically it should at least run.
EFB055
Joined: Dec 2005
Posts: 13,249
Likes: 14
From: Brisvegas, QLD, Australia
Re: OBD1 ECU problems
Update, belt walk has been solved. Somehow the guide washer which had been sitting inside the crank pulley on the floor with the shaft key not only failed to be installed, but has also completely disappeared. Tore the garage apart looking for it only to settle on getting one from picknpull.
Checked my wiring again, checked my fuse box, no blown fuses, but still have to re-prime the fuel system every single time it dies before it will start again. Continuous cranking will resolve in an intermittent splitter as if it’s TRYING to start, but no fire.
So Next step would indeed be pump and FPR? Correct me if my formula is inaccurate, but I’m getting 79,000cc/h or 79l/h out of my pump, but my injectors are 750cc/min x4 (3,000cc/min) x60=180,000cc/h or 180l/h. If that is correct, would the 190l/h suffice? (which I’m finding rather difficult to find, everyone seems to have 255 and 342l/h pumps) or as far as duty cycle should I just spring for the 255? Price is comparable between the two.
Checked my wiring again, checked my fuse box, no blown fuses, but still have to re-prime the fuel system every single time it dies before it will start again. Continuous cranking will resolve in an intermittent splitter as if it’s TRYING to start, but no fire.
So Next step would indeed be pump and FPR? Correct me if my formula is inaccurate, but I’m getting 79,000cc/h or 79l/h out of my pump, but my injectors are 750cc/min x4 (3,000cc/min) x60=180,000cc/h or 180l/h. If that is correct, would the 190l/h suffice? (which I’m finding rather difficult to find, everyone seems to have 255 and 342l/h pumps) or as far as duty cycle should I just spring for the 255? Price is comparable between the two.
Raceworks Calculators - Injector Flow Calculator - Raceworks
For example.
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From: the Evergreen state
Re: OBD1 ECU problems
Problem with that is i’d still have to order new injectors, make/buy jumper pigtails, and order another ECU tune and chip, because the only injectors I have are the RDX 750’s, (sold my Bosch N1 EK set when I started my swap) and the ECU came chopped with the 750cc tune, swing as I’d ordered it that way having already had the injectors, and therefor didn’t come with a stock tune
was considering fuel pump and regulator because that’s cheaper than new injectors plugs and tune.
was considering fuel pump and regulator because that’s cheaper than new injectors plugs and tune.
EFB055
Joined: Dec 2005
Posts: 13,249
Likes: 14
From: Brisvegas, QLD, Australia
Re: OBD1 ECU problems
Problem with that is i’d still have to order new injectors, make/buy jumper pigtails, and order another ECU tune and chip, because the only injectors I have are the RDX 750’s, (sold my Bosch N1 EK set when I started my swap) and the ECU came chopped with the 750cc tune, swing as I’d ordered it that way having already had the injectors, and therefor didn’t come with a stock tune
was considering fuel pump and regulator because that’s cheaper than new injectors plugs and tune.
was considering fuel pump and regulator because that’s cheaper than new injectors plugs and tune.
Question is, are they ok operating at OEM pressures? Can someone else chime in?
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From: the Evergreen state
Re: OBD1 ECU problems
So I’m an idiot. After not getting any injector pulse, I had tested the plugs at the ECU for power. There wasn’t any. So I had them switched back to my PM6 computer to see if it had any power output, and it didn’t and it wouldn’t fire either. That’s when the car was pushed out of the garage to work on other cars. I just realized I still had the PM6 hooked up after changing the main relay.
Plugged in the P28 and after a few seconds of hesitation and spluttering, she fired up and ran for 5 seconds before stalling. After that it will not start AT ALL. I have spark, the spark plugs have fuel on them and all 4 cylinders smell strongly of fuel, but even with starting fluid it won’t start.
Plugged in the P28 and after a few seconds of hesitation and spluttering, she fired up and ran for 5 seconds before stalling. After that it will not start AT ALL. I have spark, the spark plugs have fuel on them and all 4 cylinders smell strongly of fuel, but even with starting fluid it won’t start.
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From: the Evergreen state
Re: OBD1 ECU problems
Timing is 1/2 tooth off since I still have the Z6 cam gear, compression was good before I did my head swap, and my head was rebuilt before I installed it. So unless 4.75* is enough to make it impossible to run or it somehow miraculously blew a brand new valve or a set of rings in 5 seconds below 4000rpm (knowing the 4.75* advance would reduce the safe redline rpm, I didn’t rev past that for the time being) compression and timing should (in theory) be sufficient
. When It fired up it seemed almost like trying to start a flooded engine. Once it cleared it revved just fine for 5 seconds, and then died, never to fire again.
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