Resolved 1G Cranks but won't start

[Gracer]

Car is 92 6-bolt AWD. 1G block/head, 2G MAF/hard pipe w/pigtail. 14b/7cm hot side, full three inch. Side mount. Boost set to 14psi. Stock ECU non-EPROM.

Car was becoming more difficult to start when cold, but fine when warm and fuel pressure still in rail. Just replaced CTS as engine code came on. Car has also recently thrown codes for TPS and BAP (MAF).

The other day car died while going down a hill and the fuel light was just starting to flicker on. Put in two gallons of premium and fired right up. The next day car engine would crank but not start. Wally 255 was getting loud and whiny so replaced it with brand new rewired Wally 255. No dice. I have an AFPR and the pressure was set to 60psi on 450's. Pressure gauge reads 60psi up on first start and then falls to 10-20psi and won't move when trying to turn engine over.

Checked coils, plugs, starter, battery, alternator gtg

Replaced fuel pump, CTS, battery, clutch safety switch.

Set timing to 8° with 93 pump gas

Checked fuel pump relays, gtg

Thinking it's a fuel delivery issue.
Could it be fuel pressure regulator or something else? ECU? Dirty/clogged injectors?

I don't currently have a tuning device.

Car drove great for last month/1000 miles

Any help would be greatly appreciated!!!

 

[steve]

When was the last time you checked the compression? What was it?

Please set the base timing to 5* BTDC.

Please lower your base fuel pressure to 36-38psi with the vacuum line disconnected and plugged. Then make sure that the fuel system can track boost pressure. Make sure you new fuel pump isn't leaking into the tank when the pressure rises. It's not unusual for a Walbro pump in a 1G to leak at the interface on the hanger.

Make sure your battery is fully charged.

Get something to tune with, if you can't afford DSMLink, get an SAFC so you can correct for the lower airflow counts that a 2G MAF outputs when compared to a 1G MAF.

Make sure you don't have any more fault codes.

Make sure your CTS is functioning.

Verify that your ECU powers up. When you turn the ignition on the CEL should light for 5 seconds and then go off, the factory boost gauge should move to 0 and then drop while cranking.

 

[1cleangsx]

Have you checked your fuel filter?

 

[Gracer]

Ok thanks Steve lots to check.

I think the ECU is good at least because it does exactly what you said.
I don't remember the compression numbers. Last time I checked but they were all within two PSI of each other. I will go check these things now.

I made sure to put the nipple end of the pump way up into that rubber gasket on the hanger and then there's a plastic piece I also used a insulated rubber that goes around the pump and a couple zip ties and then the rubber bumper on the end to make sure everything is really snug!

Can I keep the 2G mass air flow hooked up it ran a lot better than the 1G hacked canister ever did. And with that do I still keep the fuel pressure that low or do I bump it to 44-43.? The car felt more powerful when I cranked the fuel pressure tbh but I understand we want to get it back to baseline.

Have you checked your fuel filter?

Oh yeah I also just replaced the fuel filter so yes

 

[pauleyman]

Can I keep the 2G mass air flow hooked up it ran a lot better than the 1G hacked canister ever did. And with that do I still keep the fuel pressure that low or do I bump it to 44-43.? The car felt more powerful when I cranked the fuel pressure tbh but I understand we want to get it back to baseline.

You have no need for a 2g MAF with a 14b and 450s. You're better off using stock 1g stuff and getting the car to run right with OEM settings for now.

 

[CrackedDSM]

Honestly with how ridiculously rich the stock 1G AFR maps are, the 10% less fuel everywhere is ideal. I don't think that's the problem.

You said your fuel pressure drops to 10-20 and never recovers? That's the problem. Did you rewire the pump, or is it stock/OEM wiring?

Also, I get why the fuel pressure was bumped to 60psi over the stock 37psi for a 1G M/T, but JESUS that's a lot of extra fuel. Lol. Even with the amount you'd subtract from running a 2G MAF on the car. I'd dial the fuel pressure down to 37 with the vacuum hose off of the FPR and the port blocked with your finger. Make the pumps job easier.

Honestly, I'm suspecting wiring to the pump, or the pump itself to be the culprit. I'm also suspect on how good the 2G MAF is. I'm curious though, before you mess with anything, unplug the MAF entirely. Does the car start?

 

[Gracer]

Honestly with how ridiculously rich the stock 1G AFR maps are, the 10% less fuel everywhere is ideal. I don't think that's the problem.

You said your fuel pressure drops to 10-20 and never recovers? That's the problem. Did you rewire the pump, or is it stock/OEM wiring?

Also, I get why the fuel pressure was bumped to 60psi over the stock 37psi for a 1G M/T, but JESUS that's a lot of extra fuel. Lol. Even with the amount you'd subtract from running a 2G MAF on the car. I'd dial the fuel pressure down to 37 with the vacuum hose off of the FPR and the port blocked with your finger. Make the pumps job easier.

Honestly, I'm suspecting wiring to the pump, or the pump itself to be the culprit. I'm also suspect on how good the 2G MAF is. I'm curious though, before you mess with anything, unplug the MAF entirely. Does the car start?

Yeah I have no problem turning the fuel pressure back down it seems like it runs okay anywhere from about 40 PSI and up anything below that it really bogs down.

The 2G mass air flow must be working because when I unplug it the car idles super low when it was running anyway or even dies so I know it's doing something.

I have the pigtail harness to go to the 1G connect

 

[CrackedDSM]

Yeah I have no problem turning the fuel pressure back down it seems like it runs okay anywhere from about 40 PSI and up anything below that it really bogs down.

The 2G mass air flow must be working because when I unplug it the car idles super low when it was running anyway or even dies so I know it's doing something.

I have the pigtail harness to go to the 1G connect

Yeah, but has it started since then. If the MAS dies entirely, I've seen the car start up and idle with it unplugged but any throttle input kills the engine. That's what I was getting at. If it does that now, but it won't start with it plugging in, you've found the problem. It's a free and easy test.

 

[Gracer]

You have no need for a 2g MAF with a 14b and 450s. You're better off using stock 1g stuff and getting the car to run right with OEM settings for now.

I know what you're saying, I have a 14b but it also has the 16g 7-8cm hot side with the 34 mm wastegate and a 3 inch turbo back cat delete.

It is only 450 CC injectors but I have the fuel pressure regulator so I can turn up and essentially turn them into 550s. I know it's not ideal but it definitely adds a lot more power and it should equal out with the 2G mass air flow. Once I switched to the 2G the car ran a lot better and smoother to be honest.

Yeah, but has it started since then. If the MAS dies entirely, I've seen the car start up and idle with it unplugged but any throttle input kills the engine. That's what I was getting at. If it does that now, but it won't start with it plugging in, you've found the problem. It's a free and easy test.

Okay I just tried starting it with the mass air flow unplugged and with it in and it's the same it cranks and shows about 300 RPMs.

I checked and there is fuel getting right up to the regulator but the gauge is reading zero now.

I also just did a compression check and it's 120, 122, 125, 122. Doesn't that seem a little low? I mean at least they're all close in comparison I feel like last time I did a compression check when the car was running fine it was similar numbers.

 

[CrackedDSM]

Okay I just tried starting it with the mass air flow unplugged and with it in and it's the same it cranks and shows about 300 RPMs.

I checked and there is fuel getting right up to the regulator but the gauge is reading zero now.

I also just did a compression check and it's 120, 122, 125, 122. Doesn't that seem a little low? I mean at least they're all close in comparison I feel like last time I did a compression check when the car was running fine it was similar numbers.

For a cold compression test on a 1G those aren't super duper concerning. They're close to the service limit but eh. I wouldn't put it down yet.

You could try to replace the diaphragm in the AFPR, but honestly if it's not making enough pressure to even pressurize the AFPR's gauge I still lean towards fuel pump and fuel pump wiring. Even with the diaphragm completely gutted you should see fuel pressure (and fuel shooting out the top vacuum port/nipple).

I'd bet Steve called it 150%. I bet the o-ring(s) has (have) fallen off and it's bleeding fuel pressure off instead of shooting it through the hose.

 

[Gracer]

Honestly with how ridiculously rich the stock 1G AFR maps are, the 10% less fuel everywhere is ideal. I don't think that's the problem.

You said your fuel pressure drops to 10-20 and never recovers? That's the problem. Did you rewire the pump, or is it stock/OEM wiring?

Also, I get why the fuel pressure was bumped to 60psi over the stock 37psi for a 1G M/T, but JESUS that's a lot of extra fuel. Lol. Even with the amount you'd subtract from running a 2G MAF on the car. I'd dial the fuel pressure down to 37 with the vacuum hose off of the FPR and the port blocked with your finger. Make the pumps job easier.

Honestly, I'm suspecting wiring to the pump, or the pump itself to be the culprit. I'm also suspect on how good the 2G MAF is. I'm curious though, before you mess with anything, unplug the MAF entirely. Does the car start?

Hey man I know it's late but if you get this you rock!!! It was the fuel pump wiring. I saw that one of the wires going into the relay looked slightly burnt. It was the ground wire actually, where I had spliced 10 gauge wire to the stock ground into the relay for the rewire kit.

A while back I had a bigger battery in the car that actually one day cut power when I was in a parking lot at idle and started a mini flame off the battery terminals. So I switched back to a smaller battery but I think that's what fried that ground wire back there. It just took a while to show that it was not making a true connection.

Yeah I know it's stupid and I got lucky I had a Dodge Stealth battery in the Talon and the top post was too close to the hood

 

[CrackedDSM]

Hey man I know it's late but if you get this you rock!!! It was the fuel pump wiring. I saw that one of the wires going into the relay looked slightly burnt. It was the ground wire actually, where I had spliced 10 gauge wire to the stock ground into the relay for the rewire kit.

Certainly sounds suspect for sure. Let us know!

 

[Gracer]

FIXED!!! It was the fuel pump wiring going into the relay for the pump rewire. I stripped some old wiring off clean and this time used crimp connectors rather than the electrical tape I had on there the past 12 years.
Thanks again guys!!!!

 

[CrackedDSM]

Ha. Three for three today. Go me.


Glad you got it sorted, man.

 

[Gracer]

Ha. Three for three today. Go me.


Glad you got it sorted, man.

 

[steve]

It was getting past my bed time It's great you got this resolved and it starts.

Please don't ignore the rest of the points. You really need a better way to tune the car than cranking up the fuel pressure. I'd bet your IDC's on the 450's have to be close to static (100%) even with all that pressure.

 

[pauleyman]

I'm in agreement with Steve. You are simply playing with fire. The larger exhaust and turbine housing don't mean much unless you're trying to push more through them. I assume you've turned the boost up. If so then it's even worse. You're making a large assumption that turning up the fuel pressure running a 2g maf and stock 450s all balances out. Since you are running 450s there is zero reason to run the 2g maf. If it "runs better" there is a reason and you should find it and fix it and not run all these compromises.

 

[steve]

Since you are running 450s there is zero reason to run the 2g maf. If it "runs better" there is a reason and you should find it and fix it and not run all these compromises.

Can I keep the 2G mass air flow hooked up it ran a lot better than the 1G hacked canister ever did.

I have little doubt that a good 2G MAF works better than a hacked 1G MAF ever did. This stuff is so OG, I remember when we used to do all this but there are so much better ways today that make our cars faster and more reliable.

 

[pauleyman]

I gotta ask did why is the car like this? Did you purchase an old project car? Steve is right there are so much better ways now.

 

[Gracer]

It was getting past my bed time It's great you got this resolved and it starts.

Please don't ignore the rest of the points. You really need a better way to tune the car than cranking up the fuel pressure. I'd bet your IDC's on the 450's have to be close to static (100%) even with all that pressure.

I will take your good advice and knowledge and get at least a SAFC

I gotta ask did why is the car like this? Did you purchase an old project car? Steve is right there are so much better ways now.

Yes I did purchase an old project car. It's the second engine and t-case I've put in it. It's been a budget project car. I want it to be a reliable dd with a little extra pep. Only 4 grand total investment with 84k miles

I'm in agreement with Steve. You are simply playing with fire. The larger exhaust and turbine housing don't mean much unless you're trying to push more through them. I assume you've turned the boost up. If so then it's even worse. You're making a large assumption that turning up the fuel pressure running a 2g maf and stock 450s all balances out. Since you are running 450s there is zero reason to run the 2g maf. If it "runs better" there is a reason and you should find it and fix it and not run all these compromises.

I had only turned up the boost to 14 psi for a short while but turned it down to around 9psi now to be safe until I can check a/f ratios

 

[pauleyman]

I had only turned up the boost to 14 psi for a short while but turned it down to around 9psi now to be safe until I can check a/f ratios

That further reinforces just get a good unhacked stock 1g maf and make sure the car runs well as is. Then make plans for what you want to do.

 

[Gracer]

That further reinforces just get a good unhacked stock 1g maf and make sure the car runs well as is. Then make plans for what you want to do.

Sounds like a plan.
I have a 1G hacked MAF I can throw back on her but it feels slower
Oh well if it's safer I'll do it until I can tune

 

[pauleyman]

The hacked MAF jacks with stuff too much. When you say hacked, elaborate.

 

[Gracer]

The hacked maf jacks with stuff too much. When you say hacked....elaborate.

I mean hacked like someone removed some of the honeycomb from the inside and cut the canister off with exposed K&N filter.

I just saw now you said UNHACKED 1G
They make those jk.
I'd have to go look for when I guess...

 

[steve]

Hacked MAF = Uncalibrated airflow.

There is not a problem with opening up the canister other than you wind up sucking it hot air right off the radiator. The fix for that is to build an airbox for it to live in that draws from outside.