The Top Mitsubishi Galant VR-4 Resource

Join the best E39A 1991-1992 Mitsubishi Galant VR-4 community and document your GVR4 journey.

  • Software Upgraded - Reset Your Password to Login
    In order to log in after the forum software change, you need to reset your password. If you don't have access to the email address you used to register your GVR4.org account, you won't be able to reset your password. In that case, follow the instructions here to regain access to the forum.

Weird no-start problem after CTS replacement

FilthyEvo

Well-known member
Joined
Jan 2, 2014
Messages
57
Location
Barrington, NH
Okay, I am having an issue here, and I will give a bit of a background before I get into what's wrong so I can get you guys up to par.

I just purchased this GVR4 #760/1000 with the previous owner stating that it had trouble starting in the cold weather. When I picked the car up, it sat for about 30 mins in the frigid cold, and started up alright - a little struggle. Once warm, the car drove very nice besides a low rpm cruise stutter (which I assumed would be a plug/wire issue or boost leak). The car then sat for a few days due to me working non-stop. The car would not start in the cold, but once we had a warm day (50*) it fired right up and I took it for it's maiden drive. The car drove VERY nice. Much better than I expected.

Fast forward to a few days ago (1/8/14), I grab new plugs (BRP7ES), new Coolant Temp Sensor, Rotella T 10w30 (the car currently has 20w50 in it), adn some various wiring items.

I pulled the LICP off, and replaced the Knock-off Greddy BOV with a crushed DSM bov (known working from my track car). I did notice that the knockoff Greddy has two vacuum port nipples vs. the DSM only having one. I'll get to this more later.

I pulled the CTS and replaced it with the new one. I also noticed that the wiring was very brittle, so I cut back some of the wire, added some new wire in and added a female connection onto both wires and hooked them up to the CTS.

While I was in there, I noticed one of the black wires from the O2 sensor plug (harness side) was broken off. I decided to cut off the plugs (since it was unsalvagable) and hard wire the O2 sensor in for now.

I also noticed that the vacuum line routing was all over the place. The WG was T'd to the BOV and it was ran to a post-throttle body source. I left the BOV running to that same source, and moved the WG to the throttle body "P" source.

I also changed the plugs, and gapped them to .028.

Now, when I went to start the car, it sounded like it wanted to start right away, but would run like it had an enormous boost leak. I thought maybe I left the MAS unplugged, but that wasn't the case. So, I went back and did a boost leak test, but heard no leaks whatsoever. Didn't really hear much at all actually.

All back together again, I try to start it, and it just sounds like it's running on two cylinders. I check the settings on the SAFC, and they are the same as when I picked the car up. I couldn't find anything that I left unplugged, or anything that was leaking. The car does not want to idle by itself, but if I keep on the gas a bit, it will idle enough that I can roll the car around. Also, when I pulled the plugs, they were pretty drenched with fuel.

Thing's I've checked/tested;

CTS - tested good
ISC - tested good
TPS - tested good
MAS - don't know how to test this
Boost leaks - none
SAFC wiring - all hooked up correctly
SAFC Settings - the settings zero'd themself out, so I set the LO settings for [(450/680) - 1] x 100 ; still nothing

There are a few random wires near the CTS wiring that are the same colors as the CTS wiring. I am very confused with the wiring because the previous owner attempted to do a wire tuck.

Things I haven't done are; compression check, ECU caps check, timing check. It doesn't make any sense to me though because the car ran beautifully before.

Any help would be greatly appreciated!

Joe
 

transparentdsm

Well-known member
Joined
Jul 27, 2011
Messages
3,690
Location
Cherry Hill, NJ
what injectors are you running? how is your fuel filter? could the injectors be clogged?

if you mixed up the yellow/green CTS wire with the a/c fan yellow/green wire then the car will not start. if you put the wires on the sensor backwards the car wont start. take a picture of what your working with and maybe i can help you.
 

vr4play

Well-known member
Joined
Feb 7, 2008
Messages
397
Location
Cincinnati, Ohio
Make sure you got the plug wires back on in the correct spot and that none of them got damaged when you did the plugs. Also take the wastegate hose off of the p port. There is not enough flow from that to open the wastegate. I did my wifes old Talon like that back in the day and wondered why it was so fast. I hooked up a boost gauge and it would peg 25 psi then boost cut. You need a much bigger boost source for the wastegate preferably right off the turbo. Here is a wire diagram that may help you with a few questions. Make sure the maf plug is good and clean.
 

FilthyEvo

Well-known member
Joined
Jan 2, 2014
Messages
57
Location
Barrington, NH
Quoting transparentdsm:
what injectors are you running? how is your fuel filter? could the injectors be clogged?

if you mixed up the yellow/green CTS wire with the a/c fan yellow/green wire then the car will not start. if you put the wires on the sensor backwards the car wont start. take a picture of what your working with and maybe i can help you.



The car has 680cc's - sorry, I forgot to add that into the initial post. I have some 450's on order. Fuel filter is new.

It seems weird to me that the injectors would just randomly clog up, after it just ran great the night before I pulled it into the garage.

Pic Below - The two extended black wires run to the CTS - they were grouped together in the harness, so I assumed these were the corrrect ones. The car seems to want to start (with this wired as is) but just runs like it has a major leak. It barely responds to the gas pedal, and pours white smoke. If I let off the gas, it will die immediately.

The green wire right up front, is folded in half and taped off (looks like two wires because it was spliced into before (I don't know why))



As I said in the OP, the O2 sensor is now hardwired. Since I found the wire broken off the plug, I am not sure if it was being used before, when the car was running well? It had to of been though, right?



Look closely below, see that single spade male connector. What is this? I have two single male connectors in my Thermostat housing, but cannot find info on this one anywhere. Two temp gauges?



See (below) the other down there (male spade connector broken off). This would be the Coolant Temp Gauge - according to diagrams I've read. So what is the other one?!



And a pic of the Cam Gears. It doesn't appear to be in time. What do you think?

 

FilthyEvo

Well-known member
Joined
Jan 2, 2014
Messages
57
Location
Barrington, NH
Quoting vr4play:
Make sure you got the plug wires back on in the correct spot and that none of them got damaged when you did the plugs. Also take the wastegate hose off of the p port. There is not enough flow from that to open the wastegate. I did my wifes old Talon like that back in the day and wondered why it was so fast. I hooked up a boost gauge and it would peg 25 psi then boost cut. You need a much bigger boost source for the wastegate preferably right off the turbo. Here is a wire diagram that may help you with a few questions. Make sure the maf plug is good and clean. url]



When changing plugs, I do one at a time so mixup does not happen. But, I did go back and check, and they are in the right location.

Okay, I will remove it from the P port. I tried starting it with the WG hose off (which wouldn't cause an issue with startup - just open boost), and still the same issue.

The MAFS plug is very hard to put on and remove from the MAFS. It doesn't "click" into place, like others have in the past. Is there a way to test the voltage getting to the plug, or to test the MAFS with a multi-meter to see if it's good?
 
Last edited:

transparentdsm

Well-known member
Joined
Jul 27, 2011
Messages
3,690
Location
Cherry Hill, NJ

It seems weird to me that the injectors would just randomly clog up, after it just ran great the night before I pulled it into the garage. - because the fuel in the tank is bad from sitting and you turning it on and running it stirred everything up and clogged everything.



Look closely below, see that single spade male connector. What is this? I have two single male connectors in my Thermostat housing, but cannot find info on this one anywhere. Two temp gauges? - this is the blue single wire in your cluster.



See (below) the other down there (male spade connector broken off). This would be the Coolant Temp Gauge - according to diagrams I've read. So what is the other one?! - that broken piece is for the dash gauge



And a pic of the Cam Gears. It doesn't appear to be in time. What do you think? - well it looks ok, but you need to turn the crank by hand and get the timing marks lined up.



 

mitsuturbo

Well-known member
Joined
Jun 2, 2008
Messages
3,544
Location
Near Seattle, Washington
^^ What he said, about the blue wire. That's where it goes, but it's not required to be hooked up for your car to run right. When the blue wire gets grounded, your cooling fans will come on. That is a thermo switch, and i believe it is related to the A/C. DSMs do not have this wire.

Quoting FilthyEvo:


All back together again, I try to start it, and it just sounds like it's running on two cylinders. I check the settings on the SAFC, and they are the same as when I picked the car up. I couldn't find anything that I left unplugged, or anything that was leaking. The car does not want to idle by itself, but if I keep on the gas a bit, it will idle enough that I can roll the car around. Also, when I pulled the plugs, they were pretty drenched with fuel.

Thing's I've checked/tested;

CTS - tested good
ISC - tested good
TPS - tested good
MAS - don't know how to test this
Boost leaks - none
SAFC wiring - all hooked up correctly
SAFC Settings - the settings zero'd themself out, so I set the LO settings for [(450/680) - 1] x 100 ; still nothing

There are a few random wires near the CTS wiring that are the same colors as the CTS wiring. I am very confused with the wiring because the previous owner attempted to do a wire tuck.

Things I haven't done are; compression check, ECU caps check, timing check. It doesn't make any sense to me though because the car ran beautifully before.

Any help would be greatly appreciated!

Joe




Your coolant temp sensor isn't sending proper signal to the ECU. I can almost guarantee it. This is exactly how my car behaved when i had forgotten to plug the CTS in after doing some work to it a few months ago. I would suggest if you do not have dsmlink or a logger, check the continuity of the wires from the CTS plug to the ECU.
 
Last edited:

transparentdsm

Well-known member
Joined
Jul 27, 2011
Messages
3,690
Location
Cherry Hill, NJ
i cant tell from the wires, but it looks like the CTS wires are mixed up pretty bad. try switching the yellow/green with the other yellow/green and see if it works. also you might need to swap the connector locations. the wires are to clustered together for me to tell just from the picture. you'd need to separate them and show me the exact two wires going there. also you shouldn't use tape like that. go get wire connectors and wire loom and cap off any wires your not using. also get waterproof female ends to go on the CTS so nothing shorts out. tube of dielectric grease as well.
 

FilthyEvo

Well-known member
Joined
Jan 2, 2014
Messages
57
Location
Barrington, NH
Quoting mitsuturbo:
^^ What he said, about the blue wire. That's where it goes, but it's not required to be hooked up for your car to run right. When the blue wire gets grounded, your cooling fans will come on. That is a thermo switch, and i believe it is related to the A/C. DSMs do not have this wire.

Your coolant temp sensor isn't sending proper signal to the ECU. I can almost guarantee it. This is exactly how my car behaved when i had forgotten to plug the CTS in after doing some work to it a few months ago. I would suggest if you do not have dsmlink or a logger, check the continuity of the wires from the CTS plug to the ECU.



Okay, so the blue wire runs to the Coolant Temp Gauge. But, that's not needed to get it running, so I'm not going to worry about that right now.

I have a logger, but I don't have the proper plug (on any of my computers) to plug the Palm into to load up MMCD. I need to see if I can find a converter.

So, there is a still a break in the line somewhere on the harness side? This would make sense since the new CTS tested good. The one I pulled wouldn't give a resistance reading at all (bad).

Once I get the logger sorted, what should I look for?
 

FilthyEvo

Well-known member
Joined
Jan 2, 2014
Messages
57
Location
Barrington, NH
Quoting transparentdsm:
i cant tell from the wires, but it looks like the CTS wires are mixed up pretty bad. try switching the yellow/green with the other yellow/green and see if it works. also you might need to swap the connector locations. the wires are to clustered together for me to tell just from the picture. you'd need to separate them and show me the exact two wires going there. also you shouldn't use tape like that. go get wire connectors and wire loom and cap off any wires your not using. also get waterproof female ends to go on the CTS so nothing shorts out. tube of dielectric grease as well.



They look messed up because they run through the O2 sensor wiring. This must have happened when I was scrambling to try different wires for the CTS. I did try both Y/G wires, and the way it's setup now, the car actually tries to run.

I used the "twist and tape" method because I was switching the wires around to see if the different Y/G wires would make a difference. Once sorted, they will be properly soldered and heat wrapped.

I will get some better pictures for you right now.

Question; I read on a few various sources (DSM Tuners, DSM Talk, random google threads) that it doesn't matter where the wires run to on the CTS; is this true or false?
 

mitsuturbo

Well-known member
Joined
Jun 2, 2008
Messages
3,544
Location
Near Seattle, Washington
You need to see what is being shown as the coolant temp by the ECU. I believe if it's not hooked up right or not getting proper signal, it will default to some insanely low temperature. Of course, if the temp were actually this low, your car would probably run a little, until it warmed up and got further from the reported temperature.

The blue wire doesn't go to the gauge. It goes to the A/C system. The single spade sensor in the front of the water neck is for your gauge. I dont recall the wire color for that one.

It shouldnt matter how the wires are connected to the ECU CTS, because the sensor simply gives a resistance value between the two contacts.
 

transparentdsm

Well-known member
Joined
Jul 27, 2011
Messages
3,690
Location
Cherry Hill, NJ
one y/g goes to the bottom part of the T the other y/g goes to the broken off one next to the CTS. the other Y/G is the dash gauge. the one in the back is the blue wire. its an open circuit till the coolant reaches a certain temp then becomes a ground and turns the fans on. yes its for the a/c, but in my mind having it is also kind of a fail safe for the fan temp sensor in the rad.

yes it matters what wire goes where on the CTS it matters a lot.
 

transparentdsm

Well-known member
Joined
Jul 27, 2011
Messages
3,690
Location
Cherry Hill, NJ
Quoting mitsuturbo:
It shouldnt matter how the wires are connected to the ECU CTS, because the sensor simply gives a resistance value between the two contacts.



i just went and swapped mine, your right. it doesnt matter. ive just always gone by the manual and i thought it would run different. not sure on how it would run once warm though.
 
Last edited:

FilthyEvo

Well-known member
Joined
Jan 2, 2014
Messages
57
Location
Barrington, NH
Quoting transparentdsm:
one y/g goes to the bottom part of the T the other y/g goes to the broken off one next to the CTS. the other Y/G is the dash gauge. the one in the back is the blue wire. its an open circuit till the coolant reaches a certain temp then becomes a ground and turns the fans on. yes its for the a/c, but in my mind having it is also kind of a fail safe for the fan temp sensor in the rad.

yes it matters what wire goes where on the CTS it matters a lot.



Fans are hard wired to a switch inside the cabin.

I've tried swapping the Y/G wire and the way it is now it actually attempts to start, but idles poorly and wants to die immediately.

With the other Y/G wire, it won't even attempt to idle.

Like said, I need to get my logger going and see what the ECU is seeing. I just don't understand why the car won't idle at all now, when before (with a bad CTS) it would start up on warm days no problem.

I feel like when I was pulling off the lower IC pipe, I rustled something loose, but since the wiring is a mess, I can't figure it out. Anyone local and want to come take a look? Beer and food on me.
 

dsmless

Well-known member
Joined
Jun 12, 2008
Messages
224
Location
tucson,az
Yeah sounds like a wiring in the wrong place. Take off anything that will be on the way of getting to that wiring harness part, (IC pipes, turbo i take pipe, bov) you need to be able to have good access to them wires, get the wiring diagram and cut back all the loom, go threw every wire for the CTS. Pretty sure one is on wrong. I had to do this and its the only way to do it right. When you get the right wire on the right conector mak it with something so you cant connect it wrong in the future.
 

FilthyEvo

Well-known member
Joined
Jan 2, 2014
Messages
57
Location
Barrington, NH
That's what I'll have to do.

Not to mention the SAFC zero'd itself out, so I set all the LO base settings to [(450/680) -1 ] 100. I'll deal with this after I get it to start.

I may not get to it today, but I'll rewire everything, mark everything and report back. Hopefully I'll have my logger setup as well.

I just don't get why it would run before and now it won't. Would a bad O2 cause this type of behavior? Or a bad MAFS?
 

mitsuturbo

Well-known member
Joined
Jun 2, 2008
Messages
3,544
Location
Near Seattle, Washington
O2 sensor isn't even a relevant thing really until the engine is warmed up. It would have little to no effect on startup.

A bad MAF/wiring can most definitely make the car not run right, but i've been able to start many 4g63 powered vehicles with NO MAF hooked up at all. They generally run and idle like crap, and are hard to keep running, but yeah.. they'll usually start, at least.

An unplugged coolant temp sensor will cause the car to not even start, or to start and run like it's on 2 cylinders (at best). IMO it's an even worse condition than running without a MAF plugged in.
 

FilthyEvo

Well-known member
Joined
Jan 2, 2014
Messages
57
Location
Barrington, NH
Good to hear. (Sort of, lol).

Okay, as soon as I get some spare time, I will pull everything back out and cut back into the harness a bit more, and trace the correct wires, and go from there.

Also, I'll get my logger setup and see what the ECU reads regarding the Coolant Temp Sensor.

I really appreciate the help/responses everyone.

Edit: Just to make it clear, the car DOES start, and with some trying, I was able to back the car out of the garage and park it. It died about 6-7 times and would barely idle long enough for me to move my foot from the brake pedal to the gas. It would not rev freely at all and would barely rev up at all. It was also pouring white smoke out the exhaust.
 
Last edited:

transparentdsm

Well-known member
Joined
Jul 27, 2011
Messages
3,690
Location
Cherry Hill, NJ
maybe you blew the head gasket then.

do a compression test. white smoke is from coolant, blue is oil, black is fuel.
 
Last edited:
Support Vendors who Support the GVR-4 Community
Boosted Fabrication ECM Tuning ExtremePSI Fuel Injector Clinic Jacks Transmissions JNZ Tuning Kiggly Racing Morrison Fabrications RixRacing RockAuto RTM Racing STM Tuned

Recent Forum Posts

Top