Buzzy

This is my first post. I have an sr20det that idles but as soon as I try and drive it the engine gets super boggy and will even die. I would take it to a tuning shop but there is only one shop in mn that will work on sr motors and they are always super busy and can't get me in. I do have a lot of mods on the motor but stock bottom end. If any one can help that would be great!!

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rc1honda

Check TPS voltages. .35-.45 closed 4.5 to over 5 wide open.

Buzzy

I just checked it and it's only working on wide open throttle so I have one on order. Thank you will try and run it next week when it comes in.

Kingtal0n

boost leak test

Buzzy

Already boost leak tested like 3 times

Kingtal0n

Well it works like this

ecu -> maf -> fuel

fuel comes from having the proper fuel pressure and injectors to match the ecu (and wiring) and correct maf for the job, and no leaks.

So, your options are, bad maf, bad maf wiring, bad fuel pressure, bad/improper injectors, bad/improper ECU, bad wiring anywhere in the chain, leaking plumbing (boost leak screws with maf reading), also finally improper/faulty Coolant temp sensor or oxygen sensor might make the engine struggle as well. disconnect O2 sensor for these tests, use a wideband to verify a/f ratio manually.

notice it doesn't say anything about TPS. Car should run fine with no tps.

diagnostics should look like:
0. compression test the engine and inspect the oil
1. fill plumbing to 15PSI and verify it holds, make sure you don't pressure the crank case in the process
1.5 fuel pressure verification, put a gauge on it and use it through the rest of the diagnostics to ensure proper pressure
2. check/change/clean the maf sensor, verify the maf matches the ECU and injectors
3. replace ECU, inspect for faulty wiring, verify maf receives and sends correct voltage, noid light the injectors

Buzzy

I'll be checking my maf when I get back from work, have a brand new Bosch maf on the way which I think is better then the isis one and my ecu is tuned for that maf. Fuel pressure was good but thinks the rail has a slight vacuum leak so I ordered all new o-rings and insulators for it.

rc1honda

The car will run fine but will drive like shit and bog and have slow throttle response with the TPS outta whack.

Just saying I had similar symptom and it was the TPS. Adjusted it to the proper voltages fixed the issue.

Kingtal0n

It should run fairly normal without a TPS as long as the plumbing is setup correctly. Most people don't know or don't care enough about how to set up their intercooler volume and bypass orientation, and the maf sensor plumbing, which all plays a role in how well the ECU is going to fuel based on maf input. The ECU does not fuel based on TPS except for two things, accel enrichment and fuel cut scenario, and accel enrichment only really helps if the maf signal is laggy or inconsistent for some reasons I mentioned.

Try unplugging the TPS on a 100% stock silvia S14 1995-1998 and see it drive and run normal.

Buzzy

Alright I now have a properly working TPS sensor and new maf sensor and still isn't working.

SR20DETsilvia

Have you checked your timing? CAS seem to give odd problems sometimes..


List a mod list to better help the diag process.

s13silvia123

Where in MN????????????????????? and what shop

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Buzzy

I did check timing and adjusted it slightly but it doesn't matter anymore since I gave up and pulled the motor and got a LS to replace it.

s13silvia123

want to sell me the Short block pm me

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