Hello, I am having trouble finding the cause of two very annoying issues. I have done a done of searching in this forum and a lot of the time I find people that have had the same issues I am having, but no one seems to follow up once they fix the issue. I hear by promise that when I fix these issues I will post what it took, so that some future soul has a good data point.
My vehicle: 1994 TLC USDM. about 160K original miles on the clock
Issue #1 My speedometer no longer works. It died about a month ago while I was driving and that was it. All other gauges and lights work. The car shifts perfectly and other than not knowing how many miles I have traveled or how fast I am going everything else in the cluster works.
Trouble shooting I have already done: Checked for voltage at the VSS, we are good, VSS has voltage. I also removed the VSS and tested its pulses and it is operating correctly. I have also check the wiring at the plugs near where the engine and transmission meet, all contacts are clean and securely connected. I have also inspected the wire harness where it passes the EGR and it looks good and intact.
With this TS I have a feeling that the problem is in the cluster itself. Has anyone had this issue before? Does anyone have a recommendation for a cluster repair place. I live in southern california but I would not mind mailing my cluster out to be fixed, the vehicle is not my primary.
Issue #2 It idles rough intermittently once warm. On a cold start the RPMs are elevated and the engine is beautifully smooth. After about 10 minutes of getting warm and driving around the idle will begin to pulse at stop lights almost like I have a big cam in it. If i just ever so slightly add throttle, say increase RPM to 800 it is smooth. The other annoying thing is that it's not 100% of the time, some times I will come to a stoplight once warm and it sits right around 600 as its supposed to and it idles great. Load does not really affect it, it will do it weather in gear or neutral. It never gets bad enough that the engine actually stalls.
Background: I had a BHG about 5k miles ago, I rebuilt the head after with all Toyota parts and really put a lot of love into it, it ran 100% perfectly for about the 5k miles after, I have done a recent oil sample to Blackstone and I have no sings of BHG now so it's not that. I also deleted the EGR and PAIR system about 10k miles ago and it ran great all during that time. My TLC does have a functioning CEL but this issue has never made it come on.
What I have tried to fix it so far: Even though the cap and rotor were in good shape I replaced those with toyota parts, i put in new plugs and wires and all 6 plugs looked perfect. I have also listened to each injector with a mechanics stethoscope and they all click in a healthy sounding rhythm. fuel filter was replaced when I did the head 5k ago. The intake pipe is a custom fabbed aluminum one i built with silicone fittings on each end that have been inspected (this has been like this for 10k miles). I have taken out and cleaned the IAC. It was pretty dirty but it cleaned up nicely. I also reset the ECU, this seemed to work for about 5 cold starts and then the issue came back. I have also inspected all vacuum lines and they were all replaced recently with new toyota vacuum line.
I am thinking it might be the IAC causing this even thought I have tried cleaning it. It is an expensive part and I don't want to buy it on a gamble. Please let me know what you think.
Please help, it's driving me crazy. Thanks in advance.
My vehicle: 1994 TLC USDM. about 160K original miles on the clock
Issue #1 My speedometer no longer works. It died about a month ago while I was driving and that was it. All other gauges and lights work. The car shifts perfectly and other than not knowing how many miles I have traveled or how fast I am going everything else in the cluster works.
Trouble shooting I have already done: Checked for voltage at the VSS, we are good, VSS has voltage. I also removed the VSS and tested its pulses and it is operating correctly. I have also check the wiring at the plugs near where the engine and transmission meet, all contacts are clean and securely connected. I have also inspected the wire harness where it passes the EGR and it looks good and intact.
With this TS I have a feeling that the problem is in the cluster itself. Has anyone had this issue before? Does anyone have a recommendation for a cluster repair place. I live in southern california but I would not mind mailing my cluster out to be fixed, the vehicle is not my primary.
Issue #2 It idles rough intermittently once warm. On a cold start the RPMs are elevated and the engine is beautifully smooth. After about 10 minutes of getting warm and driving around the idle will begin to pulse at stop lights almost like I have a big cam in it. If i just ever so slightly add throttle, say increase RPM to 800 it is smooth. The other annoying thing is that it's not 100% of the time, some times I will come to a stoplight once warm and it sits right around 600 as its supposed to and it idles great. Load does not really affect it, it will do it weather in gear or neutral. It never gets bad enough that the engine actually stalls.
Background: I had a BHG about 5k miles ago, I rebuilt the head after with all Toyota parts and really put a lot of love into it, it ran 100% perfectly for about the 5k miles after, I have done a recent oil sample to Blackstone and I have no sings of BHG now so it's not that. I also deleted the EGR and PAIR system about 10k miles ago and it ran great all during that time. My TLC does have a functioning CEL but this issue has never made it come on.
What I have tried to fix it so far: Even though the cap and rotor were in good shape I replaced those with toyota parts, i put in new plugs and wires and all 6 plugs looked perfect. I have also listened to each injector with a mechanics stethoscope and they all click in a healthy sounding rhythm. fuel filter was replaced when I did the head 5k ago. The intake pipe is a custom fabbed aluminum one i built with silicone fittings on each end that have been inspected (this has been like this for 10k miles). I have taken out and cleaned the IAC. It was pretty dirty but it cleaned up nicely. I also reset the ECU, this seemed to work for about 5 cold starts and then the issue came back. I have also inspected all vacuum lines and they were all replaced recently with new toyota vacuum line.
I am thinking it might be the IAC causing this even thought I have tried cleaning it. It is an expensive part and I don't want to buy it on a gamble. Please let me know what you think.
Please help, it's driving me crazy. Thanks in advance.