New to DSM's

[KevD]

Hey guys, I'm new here and new to DSM's in general! I have had my Laser just over 2 months and believe it or not it is the very first DSM I have ever owned. It was not taken care of mechanically and I'm sure it can be resurrected to its former glory with time and patience which is why I come here After reading over the site looking for a solution to a specific problem, I have concluded that this MAY be a possible venture.

On to the issue at hand. As I couldn't find the solution, I figured I'd ask. The car runs perfect(considering) MOST of the time. What puzzles me is what happens when I try to "play".

I can drive with moderate acceleration without issue as long as I keep my shifts to around 3500...any higher with hard acceleration and I run into what seems akin to a "fuel cut" or "limp mode" type of thing that I have read here more times than I can count!

I can make this happen any time I want by launching hard through 1st and 2nd with high 4K shifts but once part way through 3rd it just cuts out...never stalls or dies...just cuts out....

At this point, my only viable throttle range is between roughly 1400 and 1900...and if I leave my foot on the throttle will cut at 1900ish and "bog" till 1400ish then kick back in till 1900ish and start the cycle all over again.

NOW, oddly, I can more often than not get it to snap out of its funk by engaging the clutch(while driving) and revving the crap out of it....

I sorta suspect either a TPS or the ECM as the fault but wanted to pose the question to the masses for a little reassurance...

Thanks for any and all assistance that anyone can provide

 

[KevD]

check your IAC

ok...at the risk of eating crow, you may have been correct. Im still waiting on new parts, but through incessant research, I have found someone who had the EXACT same problem from his description. His repair? He replaced absolutely everything along with a full motor rebuild, STILL HAD THE PROBLEM . So in a last ditch effort, swapped out the IAC..... problem gone! !

So, I ask this again.. of everyone this time...

What the hell does the IAC have to do with an open throttle situation that could create a type of limiter right around 2k??????

 

[KevD]

Today I was playing around with our diagnostic machine at work. Im still waiting on parts but I thought Id use it to check a few things out. I found that my IC motor doesnt work...at all!... also found that my TPS was set completely wrong. After setting it like it should be, the car ran(barely) at 450 rpm......this is when I found out the IC motor didnt function. With the TPS set properly, it also made my current issue extremely more prevalent...which leads me to believe that is why the tps was so out of whack cause thats where it would run almost right....so I had to set it back to the wrong settings to make it run...although I still had the cut out issue.

Now...for a weird assed revelation....

I WANT to do a full emissions removal, so I had previously disconnected the purge solenoid and capped the vac line from the TB. Today, I removed and capped the vac line down to the egr. After doing so, I took it for a drive and that cut out problem was GONE!!!

Now this leads me to of course NOT blame the egr, but infact point me to the O2 sensor giving out a whacked reading under certain conditions. As this worn old 1.8 burns some oil, and clearly has the fuel settings screwed up, adding the egr into the mix must overwhelm the O2 and it simply says SCREW IT and shuts shit down....which also makes some sense why cycling the throttle can clear this condition up temporarily....

Of course.... I could be totally wrong and just got lucky.... thoughts???

 

[KevD]

check your IAC

What say we kick a dead horse here......

after months of just "dealing with it"..... i finally got around to do some serious troubleshooting. All sensors seemed to be ok until i got to the "IAC"....now lets face it....this is a 1G 1.8....after doing my research, it doesnt HAVE an IAC but more simply an idle control motor. No valve, just a motor. But this motor DOES have a sensor combined with it and either the motor shorted or the sensor did because when the 4-wire connector for it is unplugged, the problem I was having disappears completely.

Let me step back a bit here, the reason I HAD to look into this now is that it was now faulted at all times. Therefore, when i have the throttle opened to what should be around 2500, it would surge between 1700-1950 all the time regardless. SOOOO..... I looked into it, and when unplugging the idle control solenoid/sensor, it instantly jumped to a smooth 2500. Plug it back in and it starts surging again. Now, I havent replaced it yet but am just running with it unplugged and it runs great!! Bit of a pain on cold start-up right now cause it wont stay at idle on its own (DUH!), but once it warms up a bit its fine.

In short, dsm03, you were KINDA right in what you were saying, even if it was for the completely wrong meaning .

 

[DSM1G90]

Doing idle on a 1990 1.8 is a two step process. Please read below:

1991's up to 1994 is a different process due to slight inprovements of the system.

-You need to get the vehicle warmed up first.
-Check the idle speed with the t-cable is slack and adjust the outer idle speed ajustment screw.
-Then, turn the inner screw (fast idle adjustment screw) until RPM's start to rise.
-Turn off the engine and check the TPS voltage output settings of .48 to .52vdc. If incorrect, roll the TPS til correct output voltage is reached.

 

[KevD]

Doing idle on a 1990 1.8 is a two step process. Please read below:

1991's up to 1994 is a different process due to slight inprovements of the system.

-You need to get the vehicle warmed up first.
-Check the idle speed with the t-cable is slack and adjust the outer idle speed ajustment screw.
-Then, turn the inner screw (fast idle adjustment screw) until RPM's start to rise.
-Turn off the engine and check the TPS voltage output settings of .48 to .52vdc. If incorrect, roll the TPS til correct output voltage is reached.

done and done....to a point....

all above steps I already knew about, except step 3 there im sure you back it off again one half turn if im not mistaken...

setting the idle wasnt the issue but i appreciate the process for those that dont know and happen to be looking into this thread....

 

[ghostd'GST4life]

check all of your o2 sensors

 

[KevD]

check all of your o2 sensors

All eh?....as in more than one???

Ok, I really do appreciate all the help given here on this site but PLEASE PLEASE PLEASE read the thread first!!!!..

Don't get me wrong, I'm not trying to come across as a dick, but I really hate getting advice about something that has been either tested or fixed....

To answer the above question...the ONLY o2 that I have has been tested and checked several times in fact....by more than just one person....

Now I know that in a 4G63, there are multiple o2's....this is where reading the thread actually comes in....I have a 4G37!!!....that's a 1.8 SOHC...no IAC, ONE o2....NO turbo....

Again, apologies for coming across bitter, but I have been around forums plenty and have run across this same "non-reading" thing way too often....

Also.....just a note....this issue has been resolved!!!! See previous posts for the results....

 

[jcarmichael]

go to thread tools at the top and click solved just read over the whole thread seems you got alot of help here and actually did alot of searching to fix the problem for yourself. good to hear