New e28 525i - won't accelerate!

[Kodachrome 151]

 525i M30b25 1983.

Ok it will move slowly off the line, but it gets to 100kph eventually and slows around 3000rpm. When driving the pedal to floor vs feathering throttle have the same feedback, kinda nothing happens.

Throttle position sensor? Air mass flap thing?

 

Possibly unrelated but the instrument cluster needles (fuel and water temp) bounce all over the place when anything electrical is used and the Odometer doesn't work.

Edited March 24, 2019 by Kodachrome

[BM WORLD 1283]

fuel pump dying ? not putting out much fuel 

 

[gjm 3258]

1 hour ago, BM WORLD said:

fuel pump dying ? not putting out much fuel 

I was going to go with a blocked fuel filter!

[B.M.W Ltd 950]

These have been known to give a lot of problems on the early Euro Bosch systems

https://www.google.com/search?rlz=1C1CHZL_enNZ752NZ752&q=Early+bosch+rev+limiter+built+into+distributor+rotor&tbm=isch&source=univ&sa=X&ved=2ahUKEwjmn8zHpuXgAhUQXysKHSUAChcQsAR6BAgGEAE&biw=1600&bih=757

But there are so many things that could cause this. Fuel supply, blocked exhaust system,Cross firing in distributor cap, air flow meter. You need to go through things methodically starting off with all the basics . Without the right gear and knowledge you might have to seek help with this. Depends on your mechanical skill level.

[Kodachrome 151]

I had an 850csi for 6years so indeed had to repair disti and ignition systems several times. The 850csi is basically two M20 motors on a single crank. On this e28 I noticed one of the HT Leads going to spark plus is fairly cracked looking.

I don't have my code reader (and I doubt it connects to this old non-obd2 interface) or any of my tools for a month. Getting married in the meantime too, this is one of the  wedding cars!

Edited March 3, 2019 by mattsimis

[Kodachrome 151]

So update, left it in with Auto38 in Wellington as I dont have my tools (or space or time sadly) to really troubleshoot firsthand. 

They found the following:

- fuel pump leaking - replaced

- swapped fuel filter - replaced

- cracked HT Leads to plugs - replaced

- cam wear / tapping noise - to be fixed later

- air meter not reading correctly - replaced

- TPS not registering WOT - cleaned and repaired

- minor exhaust leak - to be fixed later

 

They replaced the fuel pump and filter and its much improved around town apparently. 

 

I do need to replace the front shocks however, anyone got some local (in NZ) for me to buy?

Edited March 17, 2019 by mattsimis
Updated with whats been fixed thus far

[Kodachrome 151]

To update outside the performance issues the car has bad, as in non-existent shocks all round (wheels hit arches with 4 adults in car) but that was known and very spongy vague braking.. 

Despite all the above fixes it still needs the throttle feathered to not cut out on cold starts and more annoyingly its still stupidly slow. Like maybe 20seconds or more to 100kph and pushing the throttle hard still doesnt make much difference.

Auto38 told me the cam wear means performance will be off and the 525i is no pocket rocket, but this is no normal IMO. After I get back from my wedding Ill get to fixing the suspension and improving brake feel then think how much money to put into fixing engine vs buying a 3.5litre block and converting to 535i.. which i hope is about 4x power powerful than whatever this is actually outputting.

Edited March 17, 2019 by mattsimis

[gjm 3258]

For suspension, (and this depends on budget) perhaps have a chat with Chris at Suspension Tech (www.stech.co.nz). He'll probably be able to supply new shocks and strut inserts.

Performance (or the lack of it) - cold start issues could be a cold start valve issue. Do you have one of these (circled)?

[BM WORLD 1283]

1 hour ago, gjm said:

For suspension, (and this depends on budget) perhaps have a chat with Chris at Suspension Tech (www.stech.co.nz). He'll probably be able to supply new shocks and strut inserts.

Performance (or the lack of it) - cold start issues could be a cold start valve issue. Do you have one of these (circled)?

thats a m20 engine , he has a m30 , but yes they do have a cold start injector underneth 

 

[_ethrty-Andy_ 2132]

the cam may well be worn and lifters need adjusting, but it wouldnt cause performance loss to the point you are experiencing.

[gjm 3258]

1 hour ago, _ethrty-Andy_ said:

the cam may well be worn and lifters need adjusting, but it wouldnt cause performance loss to the point you are experiencing.

?

I was thinking that if lack of fuel isn't the issue (fuel pump, fuel filter) maybe too much fuel could be the cause? If the cold start  is throwing too much fuel through it might cause starting issues, and (as with a choke on a carb engine) if it's not shutting off, it could flood up?

[Kodachrome 151]

9 hours ago, gjm said:

?

I was thinking that if lack of fuel isn't the issue (fuel pump, fuel filter) maybe too much fuel could be the cause? If the cold start  is throwing too much fuel through it might cause starting issues, and (as with a choke on a carb engine) if it's not shutting off, it could flood up?

Its crossed my mind too. Is there an easy way to disable the cold start injector from pumping fuel easily.. maybe just unplugging the electrical connection?

When warm the car really fires up fast, faster than any of the more modern BMW's Ive had and have. But when cold it needs some revs not to cut out.

[KwS 2425]

8 hours ago, mattsimis said:

Its crossed my mind too. Is there an easy way to disable the cold start injector from pumping fuel easily.. maybe just unplugging the electrical connection?

When warm the car really fires up fast, faster than any of the more modern BMW's Ive had and have. But when cold it needs some revs not to cut out.

Disconnect rubber fuel hose from injector, and plug with bolt and clamp. Disconnect electrical connector. Those style cold start injectors were used on a few Bosch EFI setups in the 80s and they are known to leak and cause issues. Disconnecting the electrical connector only wont stop it leaking.

[eliongater 718]

What's the general state of your electrical system? I know with mine before I replaced the battery all sorts of weird things were happening (RPM gauge moved when you turned the indicator on, most amusing). Check you're getting at 12V at the fuel pump?

https://www.bimmerforums.com/forum/showthread.php?1051022-3000-rpm-R3v-limiter

I might be able to sort something on the ECU front.

[Kodachrome 151]

Well there is something wrong electrically, the fuel gauge and water temp gauge bounce with indicators and wiper movements!   There is a new looking battery with it. The windows go up and down very fast however, I didn't think insufficient current.

 

I suspect the regulator on the alternator?

Edited March 19, 2019 by mattsimis

[Olaf 3317]

throw earthing in there....

why not get it back in to Auto38?  You've probably enough to contend with planning a wedding. 

[Kodachrome 151]

It will go back as there is a laundry list to do. But they thought it felt just a little less than normal, presumably driving around town. I think it's much worse than that but don't have direct e28 experience. But I've had 520i's in e34 guise and while not fast, actually can accelerate and such.

 

Wedding is done, this was the (very slow and bouncy) wedding car!

Edited March 20, 2019 by mattsimis

[eliongater 718]

Send me a PM if you want to have a drive of my ETA, the suspension is pretty sad (currently deciding how deep down that rabbit hole I go), but it still accelerates fine. Always happy to talk to another E28 enthusiast also.

[Olaf 3317]

5 hours ago, mattsimis said:

Wedding is done, this was the (very slow and bouncy) wedding car!

well congrats!  

[matrox02 0]

On 3/3/2019 at 10:19 AM, mattsimis said:

 525i M30b25 1983.

Ok it will move slowly off the line, but it gets to 100kph eventually and won't budge over 3000rpm. When driving the pedal to floor vs feathering throttle have the same feedback, kinda nothing happens.

Throttle position sensor? Air mass flap thing?

 

Possibly unrelated but the instrument cluster needles (fuel and water temp) bounce all over the place when anything electrical is used and the Odometer doesn't work.

Is there a catalytic converter on your model? a plugged cat would do something like that for sure, if it does, disconnect it, tie it up to one side and take the car for a spin ( probably a loud one! ) it might be a night and day difference, if not then im fresh out of ideas

[Kodachrome 151]

4 hours ago, matrox02 said:

Is there a catalytic converter on your model? a plugged cat would do something like that for sure, if it does, disconnect it, tie it up to one side and take the car for a spin ( probably a loud one! ) it might be a night and day difference, if not then im fresh out of ideas

I'll have a look tomorrow! I know it has a minor pinhole exhaust  leak anyhow, failed WOF on it. Is a Cat a legal requirement here?

I found the hose to the cold start injector was leaking fuel, bypassed the cold start injector completely today, better at cold starting now.

I also inspected the Fuel pressure regulator  and there might be petrol in the vacuum line so ordered a new one.

[Kodachrome 151]

Forgot to check if there is a Cat,  but did change 2 grounding cables. No apparent improvement. 

Awaiting Voltage regulator and FPR to arrive in post.

[_ethrty-Andy_ 2132]

@eliongater do the E28 have the copper grounding nut on the back of the cluster like E30s do ?

 

i suspect in any case this is a sperate issue not related to the engine

[Kodachrome 151]

8 hours ago, _ethrty-Andy_ said:

@eliongater do the E28 have the copper grounding nut on the back of the cluster like E30s do ?

 

i suspect in any case this is a sperate issue not related to the engine

Spoke to Brent on the phone yesterday, very helpful fellow, he suggested the same.  Last night I changed the Coolant Temp sensor (old one was reading just a little off), Voltage Regulator and had previously changed two engine grounding points. None of this made any difference to the instrument cluster though and just revving it parked (didnt really have time to drive it) didnt make any difference to the running of the engine.

I notice the alternator doesnt really seem to charge the battery if lights are on and just idling... but doubt that has any effect on driving as any amount of rev's gets the voltage up to 13.6v.

Mostly pinning hopes on FPR at this point or Cam being so far out (seemed like a very loud rattle last night) is causing performance problems. 

 

Also from talking to Brent my "easy" drop in replacement idea of a M30B34 seem dashed due to a host of small issues he pointed out. Later research I did last night suggests a M30B28 to M30B30 likely are better drop in candidates. Thats aside from just getting the current engine working ok to at least have some driving time in an E28 though.

 

EDIT: I've been reading up how the L-Jetronic system actually works.. its pretty crude, but interestingly simple. There isnt that much to make it work or not work, food for thought. 

https://centerlinealfa.com/tech_bosch_injection

http://www.lonestar912.org/912 Tech Data/912E FI Technical Manual.pdf

http://www.type17.ch/downloads/Injection/Bosch - L-Jet - Troubleshooting.pdf

https://www.firstfives.org/faq/ljet/jetronic.pdf

Edited March 27, 2019 by Kodachrome

[_ethrty-Andy_ 2132]

yes very primative system