No Power, Running Super Rich

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bigfeller
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No Power, Running Super Rich

Post by bigfeller »

I bought a 1978 633 CSi in the summer. It’s a one owner car that was parked in 1993 and hadn’t run since.

Towed it home, drained the tank, changed all of the fluids, filters, belts, hoses, etc. It runs, but very badly. No power at all. Feels like it has about 30 hp. Running super rich.

We have replaced most of the fuel system hose, the fuel filter, the fuel pump, cleaned and checked the fuel rail, pulled, cleaned and tested the injectors. I installed new spark plugs, plug leads, distributor cap, rotor, and ignition coil.

Still runs terribly. Doesn’t want to start, finally does, runs for a bit, fouls the plugs with excess gas, stalls, and then dies.

Compression is good in all cylinders (150-155 psi). We have checked the cam timing, the ignition timing. I replace the coolant temperature sender, bought and tried another ECU, bought a rebuilt Bluestreak AFM. Still nothing.

I have taken it to two different mechanics shops, and we still have not been able to source the problem.

At this point, my only remaining guess is the crank position sensor, or the spark control unit. Am I missing something obvious?
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Ralph in Socal
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Re: No Power, Running Super Rich

Post by Ralph in Socal »

Coolant Temperature Sensor. It's blue or white/tan inserted into the thermostat housing. Sensor may be bad or signal is not getting to the ecu. Check signal to at the ecu connector to make sure sensor output is getting there

There are 2 different coolant sensors on the thermostat housing. One is for the ecu the other is for the gauge reading on the dash

Ralph
There is a very fine line between "Hobby" and Mental Illness.

85 635csi Zinno Auto
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bigfeller
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Re: No Power, Running Super Rich

Post by bigfeller »

I replaced the temp sender (the long one that plugs into the blue and white wires to the ECU) with a brand new OEM BMW part. There's another one with a red plastic cap on it but it's not actually connected to anything.

This is it:
https://www.flickr.com/photos/29157481@N07/53203828740/
Last edited by bigfeller on Thu Sep 21, 2023 3:36 pm, edited 3 times in total.
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Ralph in Socal
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Re: No Power, Running Super Rich

Post by Ralph in Socal »

Not sure which one that is with a red cap. There are 3 sensors I'm familar with- thermotime sensor/switch, Coolant Temp x2 as described before. Thermotime has a 7 second ON status if the engine is cold and that triggers the cold start valve. Unplug the cold start injector valve (csv) to see if the Thermotime switch has failed. You can also disconnect the CSV fuel line to see if that is feeding too much fuel when it's not supposed to.

Your car doesn't (shouldn't) have a crank position sensor except for the BMW Inspection Connector. I'm not well versed on that spark control unit. A friend had issues with one and I provided a known good replacement. Years ago so memory is spotty on his specific symptoms. I do have several used ones if you want to try swapping it out. Pic below is from E12 Repair Manual

You should have the stand up disrributor the has advance and retard function and maybe also centrifugal advance. Make sure you're getting proper timing advance when running

Ralph
20230917_224829.jpg
20230917_224829.jpg (1.19 MiB) Viewed 1889 times
There is a very fine line between "Hobby" and Mental Illness.

85 635csi Zinno Auto
84 528i Euro
83 635 Euro Arktik
81 528i Kastanien 5-speed
88 528e Bronzit (Granpa Car)
86 535i Auto (For Sale)
81 633 csi (retired)
emac
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Re: No Power, Running Super Rich

Post by emac »

Fuel pressure regulator on fuel rail? I had one go bad causing too much pressure and very poor running except with wide open throttle.
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zinnocoupe
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Re: No Power, Running Super Rich

Post by zinnocoupe »

bigfeller wrote: Sun Sep 17, 2023 11:56 pm I replaced the temp sender (the long one that plugs into the blue and white wires to the ECU) with a brand new OEM BMW part. There's another one with a red plastic cap on it but it's not actually connected to anything.

This is it:
https://www.flickr.com/photos/29157481@N07/53203828740/
I'm pretty sure that red capped plug is the unused dealer crank sensor, doesn't do anything anymore
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zinnocoupe
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Re: No Power, Running Super Rich

Post by zinnocoupe »

emac wrote: Mon Sep 18, 2023 7:12 pm Fuel pressure regulator on fuel rail? I had one go bad causing too much pressure and very poor running except with wide open throttle.
This is a good point, I don't see anywhere in the OPs posts where he has checked fuel pressure. I usually install a semi permanent gauge on my cars so I can always check its OK.
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1979 Euro 635ci no longer a basketcase, just a running rust bucket!
1977 530i Partially restored and running now!
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zinnocoupe
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Re: No Power, Running Super Rich

Post by zinnocoupe »

zinnocoupe wrote: Tue Sep 26, 2023 5:47 pm
emac wrote: Mon Sep 18, 2023 7:12 pm Fuel pressure regulator on fuel rail? I had one go bad causing too much pressure and very poor running except with wide open throttle.
This is a good point, I don't see anywhere in the OPs posts where he has checked fuel pressure. I usually install a semi permanent gauge on my cars so I can always check its OK. There is also a fuel delivery rate test you can preform to measure how much fuel is getting to the injectors. The test is described in the Bentley . The Bentley isn't actually for the e12 based cars but its full of good info
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1979 Euro 635ci no longer a basketcase, just a running rust bucket!
1977 530i Partially restored and running now!
1987 635csi 60K KM Garage Queen
bigfeller
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Re: No Power, Running Super Rich

Post by bigfeller »

Just installed a brand new fuel pressure regulator. Sadly, no change.

Well, it looks like I am not out of options. Time for Megasquirt.
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Steve M6
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Re: No Power, Running Super Rich

Post by Steve M6 »

Since this car was sitting for a long time, it might be possible that one or more of the injectors are stuck open. That could certainly cause the symptoms you are experiencing. I know you said you tested the injectors.
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duracel79
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Re: No Power, Running Super Rich

Post by duracel79 »

Could also be a blocked return line to the tank, would increase the pressure at the injectors.
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hornhospital
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Re: No Power, Running Super Rich

Post by hornhospital »

As has been suggested many replies back, check the fuel pressure at the rail. You are playing "throw new parts at it" while ignoring that basic test (if it hasn't been done). Just replacing the FPR doesn't guarantee that the fuel pressure is now correct. Is the vacuum line to the FPR intact? If it isn't getting vacuum from the intake, the regulator will default to full pressure.

Two things that can cause serious over fuelling are excessive fuel pressure or open injectors. When you cleaned and tested the injectors, did you pulse them to see if they fire correctly, or did you just blow through them to see that they would pass fuel? They are closed against the fuel pressure more time per cycle than they are open. If they aren't actually closing completely they are flooding the intake with fuel.
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bigfeller
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Re: No Power, Running Super Rich

Post by bigfeller »

My mechanic did test the pressure at the rail. I don't remember what the pressure was, but I do recall him putting a guage on it and being happy with the result. We pulled all of the injectors, checked to make sure none were stuck open, and looked for spray pattern.
emac
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Re: No Power, Running Super Rich

Post by emac »

bigfeller wrote: Thu Sep 28, 2023 9:34 pm My mechanic did test the pressure at the rail. I don't remember what the pressure was, but I do recall him putting a guage on it and being happy with the result. We pulled all of the injectors, checked to make sure none were stuck open, and looked for spray pattern.
Does that mean you had the injectors cleaned and flow tested? In another thread, I posted about my no start issue. Car was running perfect. Parked it for a few months and it wouldn't start. Checked everything. Spark, fuel, etc. Pulled the injectors and had them cleaned. A legit place will give you a before and after print out of the results. Car fired right up after having the injectors cleaned.
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Steve M6
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Re: No Power, Running Super Rich

Post by Steve M6 »

After considering all you have been through with your engine problem, it is becoming clear to me that you really need to concentrate on the injectors. Considering all of the parts your mechanic has thrown at your car without results, new injectors would be a very minor expense.

I changed the injectors in my 635CSi to Bosch Ford Type 4-hole. The cost was minimal. Quite frankly I don't see much difference between the stock injectors and the Ford type. Both work very well. Let us know when you get your problem solved.
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bigfeller
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Re: No Power, Running Super Rich

Post by bigfeller »

I honestly don’t think it’s the injectors because we tested them all and they put out a ton of fuel, with a nice fan pattern. No leaks detected either. Also the plugs get quite wet when it’s been on for a bit. I’m thinking ignition. I used a bulb-type spark tester and the bulb lit up but was a muted yellow, not a bright white.

Dave and Ralph teamed up and Dave sent me a new known-good Ignition Control Unit. When it arrived, I realized that it’s the 6-pin version, while my car has the 8-pin version. Upon closer inspection, only 5 of the 8 pins appear to actually be used. Can I simply pull the spade terminals out of the connector and wire them into the corresponding spots on the 6-pin connector on the new ICU? Pics are below

Image
[url=https://ibb.co/WKKmQk9]

One additional thing. One of the green wires appears to have a black splice with one side going into pin 7, and the other into pin 31D. Is this normal? Or has someone previously done some splicing? There are 6 wires in the harness; 2 black, a brown, and 3 green.
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RossDinan6
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Re: No Power, Running Super Rich

Post by RossDinan6 »

I couldn't know for sure if it is possible or not to repin and run the other module. At that point the corresponding ETMs are your friend. A study of the various pin functions between the two could tell you. I have done that sort of thing on OT equipment.
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bigfeller
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Re: No Power, Running Super Rich

Post by bigfeller »

After thinking about it for a bit, I just bought another 0227100008 unit off eBay. Incidentally, this unit is also shared by pre-84 Porsche 928s and Maserati Meraks.
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Ralph in Socal
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Re: No Power, Running Super Rich

Post by Ralph in Socal »

I saw that the 008 control unit has several applications. Please enter your vin into realoem and research the proper control unit for your car. Just to verify what should be in place.

Ralph
There is a very fine line between "Hobby" and Mental Illness.

85 635csi Zinno Auto
84 528i Euro
83 635 Euro Arktik
81 528i Kastanien 5-speed
88 528e Bronzit (Granpa Car)
86 535i Auto (For Sale)
81 633 csi (retired)
bigfeller
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Re: No Power, Running Super Rich

Post by bigfeller »

Hi Ralph,

Thanks again to you and Dave for your help thus far. I really appreciate it. I tried to pay it forward by sending a guy my functional coolant temp sender, one of the parts I replaced in my quest to track down this issue.

RealOEM lists the correct BMW part number as 12141360887, which differs from the Bosch part numbers on either of the units I now have;
0227100008 original one in car
0227100025 RalphDave ICU

The pin-outs are pretty well labelled on both ICUs, and the only difference between the two ICUs is that the original 0227100008 one has 2 x #16 connectors (16 going to the engine connector/tach and the ignition coil) while the RalphDave 0227100025 unit only has one. I'm trusting that connecting both of these #16 wires into the same #16 terminal won't cause a short, since the wiring diagrams I've seen indicate that they're commonly connected between the ICU and ignition coil anyway (see helpful wiring schematic provided earlier).

Otherwise the green wire to the ballast resistor (15), the shielded connector to the distributor (7 power and 31d diagnostic connector), and brown wire to ground (31) are all present on both ICUs. I'm going to test to see if the new one works by making up a temporary connector (male-female flat blade connectors with heat shrink to point of termination) to connect the car's wiring harness to the RalphDave ICU. I've ordered a 6-pin CDI connector from Wiesner Design Ltd, so if this works, I can effect a more permant solution by modifying the car's harness to the RalphDave ICU.

If it does not, I've also ordered another 0227100008 that I can swap in, and the wiring harness will still be fine.

I'm writing all of this down and sharing with the board in the event that this documentation proves useful to someone else.

Ralph and Dave, thanks again!
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Ralph in Socal
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Re: No Power, Running Super Rich

Post by Ralph in Socal »

I did a web search on that 0887 part number and it comes back as the 008 control unit. Sorry I do not have any 8 connector controllers.

I can't give advice on your attempts to make the 025 work. My electronics is not up to your level of knowledge. Good luck

Ralph
There is a very fine line between "Hobby" and Mental Illness.

85 635csi Zinno Auto
84 528i Euro
83 635 Euro Arktik
81 528i Kastanien 5-speed
88 528e Bronzit (Granpa Car)
86 535i Auto (For Sale)
81 633 csi (retired)
bigfeller
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Re: No Power, Running Super Rich

Post by bigfeller »

D’oh! Well, I made up the adapter/connector and tried the RalphDave ICU. No real change in running. Not better, but also not worse. I will keep experimenting, but I feel I’m getting closer and closer to MegaSquirt.
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Ralph in Socal
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Re: No Power, Running Super Rich

Post by Ralph in Socal »

Have you looked at the O2 sensor? That will cause rich condition on failure. Readings should be +1V to -1V and fluctuate between the two

Basically any failed engine tune sensor defaults the ecu to rich condition to protect the engine.

Ralph
There is a very fine line between "Hobby" and Mental Illness.

85 635csi Zinno Auto
84 528i Euro
83 635 Euro Arktik
81 528i Kastanien 5-speed
88 528e Bronzit (Granpa Car)
86 535i Auto (For Sale)
81 633 csi (retired)
bigfeller
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Re: No Power, Running Super Rich

Post by bigfeller »

My car doesn't have an 02 sensor. No 02s until 82 IIRC.
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Re: No Power, Running Super Rich

Post by GRNSHRK »

Just for clarification, my '80 has an O2 sensor, first year as this was also the first year for the cat :-"

Wish I had some input regarding your problem, but I'll keep thinking about what could cause this issue :-k

I've never had to deal with this type of problem [-(
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