SR20det not maintaining idle and engine dying. Please help.

[ZenkiDK]

Hello everyone, just picked up the car about a month ago. Previous owner did the swap (redtop) and I am just getting familiar with everything. Yesterday, after starting it and letting it idle for 20 minutes, it began sputtering, I saw the rpm drop to the point where the engine was backfiring and struggling. After shaking numerous times the engine shutoff.

Things I have found:
No O2 sensor (Not sure if it is related as the car ran fine without it up until yday)
When I give it gas, it struggles/hesitates, but once in a while the rpms do go up.
Coolant temperature is normal most of the time, but on hot days, when idling, it reaches H.
Unplugging the MAF and TPS allows the car to idle fine, but the second I give it gas it shuts off.

Things I have replaced:
ECU
O2 Sensor
Fuel filter
Temp Sensor (dash and ecu)
Spark plugs

Videos:
https://drive.google.com/open?id=0B1...U5Ea3l3N19jeW8
https://drive.google.com/open?id=0B1...FU5MmF0TWJJd00
https://drive.google.com/open?id=0B1...EZoanVnNElfbW8

I can provide more information, please let me know. Any help will be appreciated. Thanks.

[cotbu]

Provide compression numbera or leak down percentage
The other stuff is an easy fix, unless the engine is blown.

[ZenkiDK]

Just did the compression test and it came out to 130 across the cylinders at WOT.
There is also an oil leak from the oil pan.
The headgasket is a thick metal one.

Also changed the plugs, but no luck.

[ZenkiDK]

Update:

Tested the MAF and TPS with a multimeter, they are fine. However, I went to check the ECU out of curiosity, and there is a strong burning smell from it. Also, its a E5 Blacktop ecu, whereas I have a Redtop. Could this potentially be the problem?

[cotbu]

130 isn't great, and could be the misfire region but let's try something.

Idk if you have the correct ecu or if consult or the check engine light has been wired up?
So first pull codes, if the ecu doesn't have an led, then watch the cluster. If neither work turn key off.

Open the ecu take pictures. Front cover and back. You're looking for burnt traces or a daughter board, or even header pins along with popped capacitors etc.
You could have shifty wiring.

The valve cover, could be switched or painted and it may be the correct ecu. You have to verify with the engine code make sure you have the correspondence mafs etc.

What's really hard is guessing how much you know, if you know how to properly setup an Sr then, it would mean to me that you know how to set tps voltage, timing and that's been done. And you're describing your problems correctly. So it sounds to me like timing, tps, mafs, vacuum/boostleak and or a bad ecu.


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[brndck]

Things I have found:

Coolant temperature is normal most of the time, but on hot days, when idling, it reaches H.

xcuzemeWAT?

This sounds like a rather large problem to me.

[TheRealSy90]

Yeah, at idle the engine should never get hotter than operating temperature, if it even reaches it. My sr would never reach operating temp at idle with an upgraded radiator.

[battery1882]

Are you losing coolant? how does your oil look?

[cotbu]

Yeah that's a big one and I think he might be blown but didn't want to frighten the op

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[ZenkiDK]

I checked the ECU and there are no burns, looks normal from the inside. Also checked it in self diagnosis mode and the code was 55. Since the coolant temp issue was brought up, I remember that this started after I let the car idle on (H) after reading that SR's run hotter thinking that I just needed to switch the temp sensor. Also, the car started and idled fine for the month that I've owned it up until this point.

Here are some vids of whats going on.

https://drive.google.com/open?id=0B1zngFU6xcN2RU5Ea3l3N19jeW8
https://drive.google.com/open?id=0B1zngFU6xcN2OFU5MmF0TWJJd00
https://drive.google.com/open?id=0B1zngFU6xcN2REZoanVnNElfbW8

[TheRealSy90]

If you haven't yet, you need to change the cluster temperature sensor in the thermostat housing, to a temperature sensor that matches the cluster in the car. So if it's a dohc ka cluster you need a dohc ka cluster temp sensor. If it's a sohc ka cluster you need a sohc ka sensor, but your tachometer won't work.

[cotbu]

You may have the wrong thermistor, the sensor for the cluster.

What is the tps closed voltage?
I would keep it running until warmed up, then set base idle and timing along with adjust tps closed voltage to .45v.
http://www.plmsdevelopments.com/sr_setup_tips.shtml

[ZenkiDK]

Just took out the coolant sensor and I looked it up online, looks like it is the SR sensor, is there a way of confirming this visually? I'll be getting the proper one this weekend. Also checked the oil to see if any coolant was in it and its good. Next, i'll be testing the tps again.

Thanks for everyone's help.

[cotbu]

That's the coolant temp sensor (cts) for the ecu. The thermistor or thermal resistor is for the cluster, and its the one with a single wire

CTS should be replaced as well.

[ZenkiDK]

Just to confirm, both the temperature sensor and the temperature sender/switch need to match the chassis of the car.

[ZenkiDK]

Just to confirm, both the temperature sensor and the temperature sender/switch need to match the chassis of the car.

[ZenkiDK]

Update: Changed out the fuel filter, temp sensor, and temp switch/sender, no difference. I will replace the ecu on Monday. However, now the temperature gauge on my dash doesn't work. Even when I put the stock switch back in, it doesn't work anymore. Did I do something wrong?

Update 2: Figured the sensor issue out, the wiring was messed up near the sensor so when I pulled it, it came out. Just re-soldered everything and my temp gauge is working perfect and so is the cooling system. One problem down...

[Kingtal0n]

boost leak

[ZenkiDK]

Checked, no boost leak and ecu wasn't the problem either.

[TheRealSy90]

Did you change the ecu temp sensor to a ka one? Don't do that.
Leave the sr20det ecu temperature sensor, you only match the cluster sensor "thermistor" to the cluster/chassis that you're using.

[Nissan2nr22]

Checked, no boost leak and ecu wasn't the problem either.

How did you check for boost leak?

[cotbu]

Set base idle and timing adjust tps to .45v
You video shows what leads me to believe it's tps related. It could also be the aicv but that would have been adjusted during base idle and timing.

[ZenkiDK]

Did you change the ecu temp sensor to a ka one? Don't do that.
Leave the sr20det ecu temperature sensor, you only match the cluster sensor "thermistor" to the cluster/chassis that you're using.


I did change it to a KA one, but just changed it back after reading your reply.

I will check the TPS again.

[cotbu]

Put it in timing mode set base idle and timing (via timing light), adjust tps to .45v closed. After this test the engine with a Rev Rev to 4500 or so then slam throttle shut engine should not stall. Should recover if your bov opened then closed, idle might dip but should return if it stalls open up the aicv some, that's why it should be centered prior to initial setup. After that check timing and if need be, adjust. I like 15° and 850rpm idle
If you can't bring your idle down or make it stable let me know. Good luck

[Kingtal0n]

130 compression across the board is fine, it means the engine has 130-200k miles and is completely normal for this age of engines.

When the engine shuts off after running a couple minutes its usually
1. boost leak
2. fuel pump related

diagnostically watch the wideband as the engine tries to die, try to keep it running by playing with the throttle while watching the wideband.

If you dont own a wideband you need to stop messing with the car until you get one. In the mean time you can watch fuel pressure instead.

[cotbu]

Lol also go over your mafs wiring, I thought you only unplugged the tps. Try disconnecting either one, 1 at a time but do both. SEe if there's any difference. Think about setting up your engine, like you just did the swap yourself.

[ZenkiDK]

Cotbu, the MAF and TPS both need to be unplugged in order for the car to maintain idle(see video 3). I tried one at a time and the engine still dies. I'm starting to think it might be a wiring issue.

TPS closed is .5 and WOT is 4.36ish. Opened the throttle and it was a gradual increase, which I believe is within spec.

Also, I just found the knock sensor to be disconnected and connected it, not sure if it might be related.

[ZenkiDK]

Update:
MAF voltage- power: 10.49 signal: .85
Only code I get from the ecu is 55.
Car runs super rich, smoke everywhere, I'm stumped.

Also, just to confirm before I return it, the KA coolant sensor will not work with the SR? Im assuming the obvious: diff motor/ecu.

[ZenkiDK]

Just checked injector resistance and all are 11.6 except the third one from the firewall, it has a resistance of 16.2.

[Kingtal0n]

boost leak lol

[justinbyrant]

just to add, the ecu doesn't really matter all the much red top to black top, the only difference is the 02 sensor which will make it run a little bit off as in a little bit rich or lean but it should still idle and run fine, problem is definitely an air leak, mine does the same thing except if I keep it running long enough to warm up it does the idle bounce like cars with vacuum leaks do, just gotta find my leak

[ZenkiDK]

Even if it is a boost leak, shouldn't the car be dying with maf and tps unplugged too? Yet it's holding an idle.

[cotbu]

nope its safe mode. uses different programming. look at you videos the one with tps unplugged the car immediately dies. the one with mafs and tps unplugged it runs. what happens when tps is plugged in and mafs in unplugged? When it runs the idle is high which would indicate vacuum leak, that iacv line might be sucking in air.

[rellik27]

If it idles fine in safe mode, check your intercooler piping. A coupling may have popped off making the engine suck in unmetered air.

[ZenkiDK]

Cotbu, when TPS is plugged and MAF is unplugged the car still dies, and same vice versa. I will have another look at all the IC piping. The problem is getting worse, it dies even quicker with those 2 plugged in and has trouble starting now.

[Kingtal0n]

The diagnostic tests are

1. compression test
2. spark test
3. fuel test

You obv have spark. I would do a compression test to double check they are all even.

Then, just fuel left. You do these:
1. fuel pressure gauge
2. boost leak test
3. observe wideband

and done

[ZenkiDK]

Solved: Low fuel pressure, bad walbro fuel pump = not enough fuel to keep engine running.

Thanks for everyone's help!

[Mcflurry]

Hahahaha I love the internet mechanics on this forum. They'd sooner retune your car than perform basic troubleshooting.

Glad to hear you got it sorted mate.