rb20det wontfire/cough, only turnover

Post by **manlove891** » Wed Oct 12, 2022 9:37 am

car is 1992 Nissan ceffy rb20det. has fwd intake pl, fmic

so this is what happened,
hurricane ian had some fun and now i try to clean up the mess.
ive gone over everything, i have spark(pulled plugs and verified spark), i have fuel( pulled inj and watched them spray).
ive tested all 12vpins on ecu and all grounds which check out.
water was up to the dash. ecu fried out. ive replaced the ecu.

car was running prior to flooding. when i did first start after flooding with new ecu i get nothing, not a whif/cough/sputter, nothing whatsoever.
tried starting fluid in the intake still nothing.

. not sure if this could be related, or how it happened. but water was in the fmic, and a little bit in the turbine, however water never went into the intake.

both green relays by the ecu click on and off. and ive cleaned all the connectors to the best of my ability with cleaner.

am i missing something?

Post by **manlove891** » Wed Oct 12, 2022 9:53 am

one thing i forgot to mention is the jecs resistor. it has no power going to it, could not verify if it should have continuity or power, ive read its for the injectors but ive verified injectors are spraying

Post by **manlove891** » Wed Oct 12, 2022 12:16 pm

ive just put the timing back to tdc and put cas back on, waiting for battery to get charge back but with fuel spark and timing relative it should sputter cough or something right?

Post by **VStar650CL** » Wed Oct 12, 2022 12:51 pm

Yep, it should do something provided it can breathe and that the plugs aren't fouled. Nothing Nissan will start easily with fuel-fouled plugs, even with starting fluid. Make sure they're dry and have an assistant check the tailpipe when you crank it to make sure it's moving air (it wouldn't be the first time I saw pounds of caked mud inside an exhaust system after a flood).

Post by **manlove891** » Wed Oct 12, 2022 12:58 pm

tailpipe sucked in air when i put a shop vac on the turbo tried using the blow function to get air to blow out of the tail but could only get air to suck in. but considering it had suction its not clogged.
is there any difference between the 2 ecu pinouts? i can only find a generic pinout not specific to 4u00 and 4u01

Post by **manlove891** » Wed Oct 12, 2022 1:16 pm

one thing i will note, i may be way off and the battery is just low but the engine almost sounds flooded with dry cylinders. when i put the plugs in and crank for a while the plugs are pretty dry could anyone tell me if the jecs resistor should have power or anything like switched 12v or something? on the electrical side ive checked ecu pins on all grounds and all 12v. that resistor i cannot find verification on

Post by **VStar650CL** » Wed Oct 12, 2022 1:45 pm

The JECS is a dropping resistor for low-voltage injectors. If your ride has one, then it should have power to one side and power through the resistance to the other side. If only one side shows power with the key on then the resistor is bad. The injectors won't run without it.

Post by **VStar650CL** » Wed Oct 12, 2022 1:48 pm

PS - Try something combustible like Brakleen or Gumout down the barrel, if injectors are the issue then it should spin up on supplemental fuel. Don't use starting fluid. You can blow s*** up with that, especially on a turbo.

Post by **manlove891** » Wed Oct 12, 2022 1:58 pm

i pulled the injectors and verified they spray but cylinders seem dry. i double checked the resistor for current with ignition on and it has no power. this was the only part i could not verify working properly. where is that wired to? i would need to chase the line to find out why there is no power to it unless someone can tell me where to check

Post by **manlove891** » Wed Oct 12, 2022 2:02 pm

as far as supplemental fuel am i spraying into the turbo? do i pull the cold side ic pipe and spray into the intake?
i think i have tried both but during the time i had the cas out, not since i put it back to tdc and reinstall cas

Post by **VStar650CL** » Wed Oct 12, 2022 2:04 pm

Should be wired someplace in between power and the injector+ terminals, but on a Ceffy your guess is as good as mine about the routing. Later injector styles don't need it, so if the engine was ever updated it's probable the JECS is disconnected and jumped out.

Post by **manlove891** » Wed Oct 12, 2022 2:07 pm

it has always been plugged up and im stock injectors and rail. mine is located on the turbo side on the wheel well just behind the headlight

Post by **VStar650CL** » Wed Oct 12, 2022 2:35 pm

Then you'll need to find out which relay should be powering it and trace why either the relay isn't turning on or has no supply. Could be a blown fusible link, I'd check those first.

Post by **manlove891** » Wed Oct 12, 2022 2:56 pm

i do believe there is a fusible link however im not positive on what they look like on the loom just before it goes through the firewall. i got the car with the swap. mechanically i can build rb but i dont know anything about the electrical. the piece im talking about is small has 2 wire its prob 1.5x1/4x1/4. im going to check it out once the rain stops.
will post what i find out, possibly with pics

Post by **manlove891** » Wed Oct 12, 2022 3:22 pm

this is what i was referring to, shows 12v on both sides so it is good regardless.

Post by **manlove891** » Wed Oct 12, 2022 3:26 pm

this is another fuse i believe that has 2 posts was sitting under iac wrapped to the rail loom. when plugged in when i probe one side it is 12v when i probe the other terminal its 0. looks more like a relay then a fuse.

Post by **manlove891** » Wed Oct 12, 2022 3:45 pm

lets start back at the basics,
air- good
fuel- good
spark-good
for electrical can someone walk me through the basics of what and how to check?

Post by **VStar650CL** » Wed Oct 12, 2022 4:11 pm

That thing you were wondering about is a capacitor, probably there for noise suppression. If you put an ohmmeter on it the reading will start high and then gradually drop off as your meter charges the cap. The 0V side will be connected to ground.

You said the plugs seem dry, do we know the injectors are firing during cranking? Or just that they're working when tested?

Most later Nissan ECU's get their spark timing from the crank and injector timing from the cam, but if your Ceffy CAS has a dual wheel like the old dizzies then the wheel is doing both with two different signals, a set of coarse holes and a set if fine holes. Both need to work for everything to fire at the right time. You might just try rotating it during cranking and see if the change in timing wakes anything up.

Also, have you checked for water in the crank? Water is thinner than motor oil and even healthy seals won't always keep it out under pressure from a flood.

Post by **manlove891** » Wed Oct 12, 2022 5:19 pm

the rb20det was not factory in mine. was pulled from a r32 gtst so regular rb20 cas, nothing special. loom is not long enough to rotate 360. i manually tested the injectors on the rail by spinning the cas. all 6 spray gas. ive also tested the gat at the rail feed, let it sit with no separation. threw it to the driveway and it ignited right away so gas is good

Post by **manlove891** » Wed Oct 12, 2022 5:25 pm

if water was in the crank wouldn't it be in the oil pan?? the water should sit on top of the oil or should be milky but when i pull the stick it is not

Post by **VStar650CL** » Wed Oct 12, 2022 5:58 pm

Yep, just making sure you checked for it. Water is insidious, and it only takes a little in a bad place to cause headscratcher problems.

Post by **manlove891** » Thu Oct 13, 2022 5:34 am

could really use an rb god right about now..... can someone please list any fuses relays or sensors i should check. will crank but no fire. spark has been verified, fuel does squirt when not on the block, cas is properly functioning the injectors and the sparkies when key spindle is spun.im out of ideas as to why this thing wont fire.

Post by **manlove891** » Thu Oct 13, 2022 5:59 am

ecu code is 55 as well

Post by **VStar650CL** » Thu Oct 13, 2022 7:02 am

Is there water in the fuel, maybe? I can't help you much with Ceffy specifics, I'm sure you know the FSM's are rare as hen's teeth and mainly Japanese. Catch some fuel coming out of the injectors and see if it will burn well.

Post by **manlove891** » Thu Oct 13, 2022 7:09 am

so i pulled injectors and verified spray, i pulled fuel line just before the rail let some fuel sit to see if it separated, it did not. threw the gas onto the driveway and lit it up which it ignited instantly so gas is good.
i put a socket extension into the cylinders and spun the cas to see if the injectors will get the extension wet, but upon finishing the extension was dry after maybe 3-4 injector clicks at each cylinder

Post by **manlove891** » Thu Oct 13, 2022 7:13 am

everything electrical on the ceffy harness seems to be working with the exception of the radio, and my jecs power meter. it is fooked and ive not pulled it out yet.

Post by **VStar650CL** » Thu Oct 13, 2022 7:26 am

Take a look at your fuel pressure. Maybe there's a problem back at the tank or in the lines that's only letting a trickle of fuel through.

Post by **manlove891** » Thu Oct 13, 2022 7:28 am

fuel pressure reg holds 40psi during crank

Post by **manlove891** » Thu Oct 13, 2022 7:51 am

grabbed a flash light and i can see mist on cyl 1 and 6 when i spin the cas so i am getting gas. 100% getting spark. no combustion though. when i put the plugs in it almost seems hard to turn over. im so lost with this car right now

Post by **manlove891** » Thu Oct 13, 2022 7:52 am

even if i use starting fluid i get nothing still. even out of time the starting fluid should make it backfire cough or something

rb20det wontfire/cough, only turnover

rb20det wontfire/cough, only turnover

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Re: rb20det wontfire/cough, only turnover

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Re: rb20det wontfire/cough, only turnover

Re: rb20det wontfire/cough, only turnover

Re: rb20det wontfire/cough, only turnover

Re: rb20det wontfire/cough, only turnover

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Re: rb20det wontfire/cough, only turnover

Re: rb20det wontfire/cough, only turnover

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Re: rb20det wontfire/cough, only turnover

Re: rb20det wontfire/cough, only turnover

Re: rb20det wontfire/cough, only turnover

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Re: rb20det wontfire/cough, only turnover

Re: rb20det wontfire/cough, only turnover

Re: rb20det wontfire/cough, only turnover

Re: rb20det wontfire/cough, only turnover

Re: rb20det wontfire/cough, only turnover

Re: rb20det wontfire/cough, only turnover

Re: rb20det wontfire/cough, only turnover

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