Fuzzydicerule Posted December 2, 2014 Report Share Posted December 2, 2014 Hey guys so looking to see if any one has any ideas for what is going on with this. The problem: So while maintaining a constant speed with the rpms between 1500-2000 the car will randomly stumble or buck. If you accelerate it is perfect all the way up. I've tried to watch my Afr gauge but it reads its typical for me --- under super light load so I don't know if it is 100% accurate. Things I've done: Had the tps upgrade on it. And set it to .5 volts same issueChanged it to a stock unit set to .5 volts l, same issueTriple checked timing at 10° It has trilogy turbos stock sized injectors a few years old now. Replaced vacuum lines I am kind of lost on this and any input would be awesome. Kind of hard to pass ca smog when you can't maintain a speed in that rpm range. Thanks for the help.Jeff Link to comment Share on other sites More sharing options...
ucw458 Posted December 2, 2014 Report Share Posted December 2, 2014 Wiggle the injector clips at idle. If it stumbles that's your problem. Link to comment Share on other sites More sharing options...
Colin Posted December 2, 2014 Report Share Posted December 2, 2014 Replace the clips anyway unless they're new Link to comment Share on other sites More sharing options...
ucw458 Posted December 2, 2014 Report Share Posted December 2, 2014 Replace the clips anyway unless they're new While I do agree, it's nice to diagnose the issue first before throwing on new parts. That way you know for sure what the problem is. Link to comment Share on other sites More sharing options...
scott87star Posted December 2, 2014 Report Share Posted December 2, 2014 Good idea to clean all the old grease out of the distributor and relube, I've seen some that I literally cannot pull apart without tools, therefore they were not advancing and retarding like they should have been. Link to comment Share on other sites More sharing options...
Starfighterpilot Posted December 2, 2014 Report Share Posted December 2, 2014 Have you taken a set of EFI ECU error codes? See FSM page 14-20 and 14-49 & 50 for analysis of the indication and page 14-61, Illustration S for the location of the diagnosis terminal. There is also a FAQ on this subject. Is the push pin on the ISC "idle nose switch" and the TB linkage plate that the ISC idle button switch contacts clean of corrosion/dirt? If either one is not making a good electrical contact, or the pin in the nose switch is stuck, I've seen the MPS/ISC cause some wierd FI stuff over the years. If the injector clips are not the problem, and you don't have any error codes, you may have a sporadically weeping secondary injector; or the primary injector nozzel tip may be starting to foul up, even tho the injectors are just a few years old. Ya might want to take both of your injectors in to a diesel repair shop that cleans & tests fuel injectors. For What It's Worth. KEN PS - You can test the engine coolant temperature sensor per FSM 14-64. Another brain fart - you are running Trilogy fuel injectors which run slightly richer that the OEM ones and consequently cause the engine to run a little ragged until the engine warms up. A bad CTS causes the EFI ECU to remain in Open loop on the fuel maps cuz it thinks that the engine is still cold.. This causes the EFI ECU to inject more fuel (ie longer injection open times) even though the engine is warmed up. See FSM page 14-13 thru 14-15 for a better explanation of Open and Closed Loop and how the sensors control the EFI ECU. Link to comment Share on other sites More sharing options...
Fuze Posted December 2, 2014 Report Share Posted December 2, 2014 (edited) I had a similar problem and it turned out to be bad wiring at the TB, specifically cracked wires for the MPS/ISC. Drove me insane until I fixed/soldered those wires and the problem was gone. It's kind of along the lines of bad injector clips, basically just 20+ year old wiring on a paint-shaker engine. I ended up redoing all the connectors soldering fresh wire in where the stock wire failed. For those who don't like solder on a car, there's a reason solid state stuff is never crimped and the same concept applies to sensors and other electronics. A crimped connection lacks the same conductivity, corrosion resistance and strength, although more flexible at the joint. That's why they break at the joint. Edited December 2, 2014 by Fuze Link to comment Share on other sites More sharing options...
Fuzzydicerule Posted December 2, 2014 Author Report Share Posted December 2, 2014 Wiggle the injector clips at idle. If it stumbles that's your problem. The injector clips haven't been replace but I have tryed wiggleing them and evdrything and it did not stumble or anything. So yeah I know I should replace them but so far they haven't shown any signs of going out. Link to comment Share on other sites More sharing options...
Fuzzydicerule Posted December 2, 2014 Author Report Share Posted December 2, 2014 Have you taken a set of EFI ECU error codes? See FSM page 14-20 and 14-49 & 50 for analysis of the indication and page 14-61, Illustration S for the location of the diagnosis terminal. There is also a FAQ on this subject. Is the push pin on the ISC "idle nose switch" and the TB linkage plate that the ISC idle button switch contacts clean of corrosion/dirt? If either one is not making a good electrical contact, or the pin in the nose switch is stuck, I've seen the MPS/ISC cause some wierd FI stuff over the years. If the injector clips are not the problem, and you don't have any error codes, you may have a sporadically weeping secondary injector; or the primary injector nozzel tip may be starting to foul up, even tho the injectors are just a few years old. Ya might want to take both of your injectors in to a diesel repair shop that cleans & tests fuel injectors. For What It's Worth. KEN PS - You can test the engine coolant temperature sensor per FSM 14-64. Another brain fart - you are running Trilogy fuel injectors which run slightly richer that the OEM ones and consequently cause the engine to run a little ragged until the engine warms up. A bad CTS causes the EFI ECU to remain in Open loop on the fuel maps cuz it thinks that the engine is still cold.. This causes the EFI ECU to inject more fuel (ie longer injection open times) even though the engine is warmed up. See FSM page 14-13 thru 14-15 for a better explanation of Open and Closed Loop and how the sensors control the EFI ECU. I've checked for error codes and got a whole lot of nothing. So I was thinking about it maybe being a coolant temp sensor. Which one is the for the ecu? The two prong or one? Link to comment Share on other sites More sharing options...
Fuzzydicerule Posted December 2, 2014 Author Report Share Posted December 2, 2014 Thanks for the input guys I'll go ahead and check those things out today if I get a chance. Link to comment Share on other sites More sharing options...
TexasQuest Posted December 3, 2014 Report Share Posted December 3, 2014 I put off replacing my injector clips for years thinking they're good enough. When the time came that I got off my lazy butt and replaced them it ran like a whole new car. Link to comment Share on other sites More sharing options...
Fuzzydicerule Posted December 4, 2014 Author Report Share Posted December 4, 2014 I put off replacing my injector clips for years thinking they're good enough. When the time came that I got off my lazy butt and replaced them it ran like a whole new car. Don't worry they are on my list of things to replace once I get some spare $ Link to comment Share on other sites More sharing options...
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