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SuperSwede

Vacuum issues / running rich?

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I guess so, got a new NGK to test with.

 

Are Renix famous for eating O2 sensors?

 

I did a major overhaul of the whole engine and wiring in 2014,  the first O2 senor i put in was a Airtex and it went bad from start...then I put in a NGK 23553 which apparently are bad today after only 5 years and  20 000 km ?

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5 minutes ago, SuperSwede said:

Are Renix famous for eating O2 sensors?

If its not a well maintained system it could. That being said I just got a NOS O2 to replace the NTK sensor(that is failing) in mine that has only been installed for 2 years and with less mileage on it.

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Nice REM you got there. O2S HEATER must work properly. Measure it for B+, ground and OPEN element on the O2S. Back to the vacuum hose going to the Fuel Pressure Regulator (FPR). Fuel Rail pressure at idle can read good both with and without the vacuum hose. But raw fuel can still leak by the FPR diaphram. Check the vacuum hose for raw fuel.


Couple of REM questions. OPEN LOOP should set Short Term Fuel Trim (STFT)=128. Do you have the same value for Long Term Fuel Trim (LTFT)? What is the INJ PW time (mS)?


Hopefully the new O2S will solve all of these problems.
 

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On 1/25/2020 at 2:23 AM, Ωhm said:

Nice REM you got there. O2S HEATER must work properly. Measure it for B+, ground and OPEN element on the O2S. Back to the vacuum hose going to the Fuel Pressure Regulator (FPR). Fuel Rail pressure at idle can read good both with and without the vacuum hose. But raw fuel can still leak by the FPR diaphram. Check the vacuum hose for raw fuel.


Couple of REM questions. OPEN LOOP should set Short Term Fuel Trim (STFT)=128. Do you have the same value for Long Term Fuel Trim (LTFT)? What is the INJ PW time (mS)?


Hopefully the new O2S will solve all of these problems.
 

The vacuum line is ok,no gas in it and the FPR holds the preassure.

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New O2 sensor but no happiness, the sensor is alive a few seconds after start but quickly goes to values as shown below.

 

Power on

Renix ignition on.jpg

 

Start and five seconds

Renix_start_first_seconds.jpg

 

After five seconds and forward..doesen't matter with high or low rpm or to give it more time, it remains the same.

Renix_start__five__seconds_and_forward.jpg

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Have you verified voltage at the orange wire for the oxygen sensor and good ground at the black wire?

 

Also, on your O2 sensors, while unplugged, get the ohms reading from orange to black wires. 

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Yes I have, all three wires are good and also  the heater resistance.

I did a full circuit from the 12V input on the heater relay thru the orange wire, thru the heater  and back thru the black wire up to  the wire harness in the engine bay where I took out the signal and then twisted and stressed the wires and connectors and all good  around 5 ohm steady as a rock.

 

(The O2 I took out was also ok regardning the heater but was dead regarding the output)

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All REM values look good for OPEN LOOP condition. If O2S is telling the truth, then raw fuel/oil fumes are coming from somewhere, otherwise I'd suspect the ECU.

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5 hours ago, SuperSwede said:

Readings on idle 

 

Data 1.jpg

Data 2.jpg

 

Looking back at the three pressure measurements at idle, manifold vacuum is 15.8"hg. Seems low (normal being 18"hg). Low reading can indicate tight engine/friction. If vacuum gauge is reading same value as REM (engine vacuum), as it should, then engine has low vacuum (call for more fuel). If they don't match maybe MAP sensor is incorrect, causing extra fuel (INJ PW=5.8mS). I think engine vacuum value is calculated (BARO-MAP). What I'm try to say is maybe suspect MAP.

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I will double check this to morrow.

The idle is low wich may explain the low vacuum but I will compare the REM with my vacuum gauge, I will also compare input/output in the MAP sensor once again.

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Did something new today since this low vacuum keep coming back in mind..

I made me a smoke generator and did a serious test with 0,5 bar  pressure from the generator.

And there was two tiny leaks, both from the butterfly axle, both hard  to see but still a leak.  But I don't belive it is possible to not have that leak if the axle should work.

 

 

This morning when I was  driving to work It was as usual no O2 output,,but when I drove home tonight it came alive twice for a minute or so after some smooth acceleration?

I could feel the difference directly but it diden't last for long.

 

 

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47 minutes ago, SuperSwede said:

This morning when I was  driving to work It was as usual no O2 output,,but when I drove home tonight it came alive twice for a minute or so after some smooth acceleration?

Or did the ECU come to life.

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ECU..the "black box of renix"

Full of 31 year old electronic components, how to diagnose it.

Capacitors for a start I think they are probably on the end of their life span, otherwise the board looks to be in surprisingly good shape and well manufactured.

In fact so good that I really don't want to start messing around with it..

 

A close inspection with magnifier and a sharp eye can't find a single bad solvering or any signs of a cracked or burned component

20200130_193357.jpg

20200130_190412.jpg

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The ECU is a pricey item for replacement, especially when it doesn't solve the problem. Did you ever run a Compression Test on each cylinder?

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Yes I did and it is 125 to 128 psi, more than good I think.

I got me a another ECU from the junkyard for 100$  but the O2 value readings are the same.

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Your vehicle is being difficult. You mention that your O2S came to life after some light accelerations. During this condition exhaust manifold acts like a blow torch and possibly heated up the O2S. I know you have check out the O2S Heater circuit for continuity and the REM shows O2S Heater voltage. But you'll need to tax (current flow) this circuit. O2S Heater element is 6ohms, so ≈12vdc÷6ohms=≈2amps. Remove O2S Heater Relay. Connect Amp Meter between Battery Positive and C228_3(87a) on the O2S Heater Relay Block. Does circuit flow ≈2amps of current?

1811326051_C228O2SRelayBlock.jpg.bf8f415431f31b8a859d4a405cb1b81e.jpg

 

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You're right,,,

I've been thinking of this to do a hard wired test while driving not only the O2 heating circuit but also the ground and the output to see if it could be any deviations due to vibrations or so.

 

 

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I measured the involved relays tonight with a high end instrument and got some weird results so it ended with that I took the wire harness apart and it was full of a green mess,,

Took away all the duck tape (original!?)  and cleaned everything with alcohol then I did a serious check of the wirings and found this..

Now I'm confused not only because of the beer tonight, look at this schedule and say what you think?

Could my O2 sensor ever have worked !?

 

 

20200207_210426.jpg

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Flukes and beers and some heavy blues from the speakers ( Hard road to travel by Bobby Radcliff..Thank you America for this guy)  in the garage , what else can you want?

 

I know...

 

The solution to this O2 mess.

 

 

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2 hours ago, SuperSwede said:

Flukes and beers and some heavy blues from the speakers ( Hard road to travel by Bobby Radcliff..Thank you America for this guy)  in the garage , what else can you want?

 

I know...

 

The solution to this O2 mess.

 

Hope those are beers & cheers and not beers & tears. Playing the Blues tune makes me think it could be the latter.

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Another weird thing found, look at the wiring diagram below.

The wires are marked yellow as they are connected in my car and does not match the diagram if this diagram is the right one?

 

If the o2 heater relay is supposed to be a standard relay with pin 85 and 86 for supply feed and the 30 C  87 NO    87A NC

the O2 heater never will have any 12 v out from the relay when energized which it is all the time as far as I can see both when measuring and reading the renix monitor

(Which I now find out reads the 12 v att the feeding pin on the relay not the actually voltage going to the O2 sensor..)

 

If I put a wire between 30 and 87A I got 2 Amps verifying the heater works, but it still runs in open loop

wiring_o2_relay_.jpg

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