Starting
Are all 300GE slow to start when cold after resting for a week, once started will restart instantly. It always fires but does not seem to make any difference if given gas or not.
mines the same but it could be that my battery is on the way out
If the engine idle at cold is not indicating between 1000/1200 rpm at start up dropping to 700/800rpm after 1 to 5 minutes depending on ambient temperature then the CIS Jetronic fuel management system is not operating as it should..probably one or more of three sensors faulty in the system..when hot it should start quickly and rev to 1000/1200rpm for 5 seconds before dropping to 700/800rpm steady idle NO roughness......all the revs are without touching the accelerator....
the fuel system is pressurised by an electric pump..try switching the ignition on and off three times before you energise the starter..if it starts quickly then the fuel filter or accumulator may be faulty or you have a perished hose/pipe fracture releasing the pressure from the fuel system prematurely..the fuel system should stay pressurised enough after 4 or 5 days for one turn of the key to boost the pressure adequately for quick starting.....
It should start immediately, within 1-2 seconds, despite the temperature. Mine fires the same from -20 to +25 Celsius(thats what we have here).
If not, basically there are three main things to check, fuel, air and ignition.
My car is from 1991 and I have changed injectors because they leaked(loss of fuel pressure). Ordered directly from BOSCH code 0 437 502 035.
Then, there was air leak caused by cold start system rubber hose (A1030940482)crack - replaced.
Changed all main HV parts from leads to spark plugs.
I'll hope you do not have more complicated problems.
Actually the Jetronic's overvoltage ralay cold solder was also repaired, the symptom was ABS light coming lit.
For troubleshooting:
Do you know that 300GE engine works fine and even starts(not so fine) completely without Jetronic's electornics.
So, if engine is cold and Jetronic's electronics are not working, engine starts, but not so easily.
It should start immediately, within 1-2 seconds, despite the temperature. Mine fires the same from -20 to +25 Celsius(thats what we have here).
If not, basically there are three main things to check, fuel, air and ignition.
My car is from 1991 and I have changed injectors because they leaked(loss of fuel pressure). Ordered directly from BOSCH code 0 437 502 035.
Then, there was air leak caused by cold start system rubber hose (A1030940482)crack - replaced.
Changed all main HV parts from leads to spark plugs.
I'll hope you do not have more complicated problems.
Actually the Jetronic's overvoltage ralay cold solder was also repaired, the symptom was ABS light coming lit.
For troubleshooting:
Do you know that 300GE engine works fine and even starts(not so fine) completely without Jetronic's electornics.
So, if engine is cold and Jetronic's electronics are not working, engine starts, but not so easily.
Some good advice there - thanks!
Apologies for slightly hi-jacking the thread, but my 1991 is having problems idling when cold, and soon as it warms up, idle gets progressively lumpier until it dies. After removing the air cleaner, I noticed the air flow meter being depressed slightly with a "rasping" sound coming from air flowing past - it never used to do this. I disconnected the idle air motor/valve and it runs fine when hot, but I have to manually raise the idle when cold to keep it running.
Will check the hoses and injectors for leaks, but I don't think they are the cause as the signal coming to the idle air valve seems to be what is causing the malfunction. Coolant temp sensor checked and resistance is within spec at hot/cold temps. Upper chamber fuel pressure is also fine (~90psi), lower chamber slightly less. I hope it's not the ECU!
Most of the HV side has been changed recently, including fuel and OVP relays.
Hi there are three sensors and the EZL relay plus any vacuum leaks can cause this cold start problem. effectively the 7th injector or increased air to support the cold start increased fuel program are inop..not easy to sort out as you only get one shot at the test and setup procedures until the engine is totally cold again...see my previous threads on the subject.if the idle motor does not get the right sensing it will not function. same setup on the W124 petrol saloon and estate.
Actually the Jetronic's overvoltage ralay cold solder was also repaired, the symptom was ABS light coming lit.
Hi, where exactly is this relay located? I have the same problem.
Open the fuse box, overvoltage relay is located in the left side(mine is LHD). You can recognize it by the fuse on the top of the relay.
Tried the power on/off three times did not seem to make any difference, the problem is that once started it starts straight away. Plugs leads cap rotor arm all changed, the manual say about 4 seconds to start, what I have noticed is noise from the fuel pump area sometimes when driving, this noise is not there when the engine is idling, only appears on light load.
Is this related?
could be faulty a fuel filter /accumulator/or an injector leaking the pressure off the system after switching off the engine....a clogged filter makes the pump groan as it tries to push the petrol past the blockage..or contamination in the fuel tank causing restricted fuel flow .....
Started the car this morning after being stood since Sunday, fired immediatley, have not done a thing to it was going to get a new fuel filter. Could this the a bad connection, car was parked in a sheltered postion ie by the garage. I am going to clean all the connections in the egine bay and see it that fixes it.
Is this likley to be the fault?
Did fill the car on Saturday!
change the fuel filter anyway, these often get missed during a service
I would start from checking the accelerator linkage microswitches and throttle position sensor.
It could be that either one of them, especially, throttle position sensor, is weared out and gives wrong reading thus making electronics to calculate wrong air/fuel mixture thus making starting hard.
If the potentiometer is weared out it can give various reading, some of which are right(thats why sometimes you have successful start)
Here is the link(in german) to throttle position adjustment giving aslso information how to check if potentiometer is ok. http://www.wochelen.de/w126/fuchs_poti/fuchs_poti.html
Your G' is fitted with BOSCH CIS Jetronic (mechanical) which is not as sophisticated as the electronic W126 2600cc engine.... with 4 basic control areas.................
1. the air mass sensor - adjusted with a 3mm allen key
2. the water temp sensor fitted at the back right hand corner of the cylinder head
3. the distributor adjustment point at the base of the fuel distributor
4. the idle motor which can be adjusted with an allen key
and the fuel filter located next to the fuel accumulator on the chassis frame close to the fuel tank.fit new if in doubt...........
loss of fuel pressure can occur ater standing overnight ..or longer and will require 3 to 6 rotations of the ignition switch to the start notch but NOT starter rotation. to build the pressure up in the system.
1 3 .and 4 are very fine adjustments by trial and error due to worn tolerances in an old engine. 2. is a replacement sensor....no computer diagnostics available on this engine.....
Your G' is fitted with BOSCH CIS Jetronic (mechanical) which is not as sophisticated as the electronic W126 2600cc engine.... with 4 basic control areas.................
I wouldn't be so sure about that.
My 1991 300GE 436 with M103.987 engine and catalytic converter is equipped with KE-Jetronic, exactly the same as the("sophisticated") system described in the german site mentioned in my earlier post. Actually catalytic converter requires more accurate fuel/air mixture control with lambda sond and ECU.
So, if "old sods" truck is/was originally equipped with catalytic converter it must have "sophisticated" KE-Jetronic. Otherwise it's K-Jetronic which is more simple control system(without ECU).
Hi the four common items listed are all in the engine area.there is an L or ELR 603 fuel pump relay and CIS E 3 ECU behind the glove box on RHD models
Even the older k-jet had an ecu and like the ke-jet it is not an adjustable or re-mappable black box, chippable or alterable system. Unlike the way more recent systems are, but that means greater reliability. Its a sort of a solid state ecu and I have never known a failure of either system either in my g-wagens or my more numerous fuel injected Volkswagens.
Checked the records it had a new fuel filter about 10,000 miles ago, it's still starting of the first turn. Now not broken, will leave well alone until next service!
I would agree if its not broke don't fix it
It broke again! :roll:
Got a new fuel filter before I could fit it the car immoblised its self, the auto electrician that wire up the unit (insurance requirement) wired most of the power through the immobliser. So cold morning lights. wipers, heated rear screen, heated seat and fan all on, distance travelled 4 miles then the printed circuit burnt out, well it would its only designed to carry the load of the fuel pump.
I waited 1.5 hours to be recovered then four days to get a auto electrician to come!
Moral of this tale is if a proffesional installs an immobilser in your car and most of the dash lights go out when the immobilser is on have the car checked otherwise you may spend a couple of hours parked on a clearway like me.
Lastly fitted the new fuel filter, instant starting all times last one according to the records on two years about 5000 miles according to the bills, never seen a two year unit that dirty!!! :shock:
Thanks for the help lads.
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Thanks for the info
Started it last night, stood from Saturday, outside temperature 24, started, it ran about 900-1000 rpm then dropped after about a minute to around 700 rpm. It just requires a lot of turning over before any signs of life.
The battery is good since the engine spins well.
There is a small misfire (uneven run) until the engine is reved, distributor cap, rotor arm etc have all been replaced.
Basically is there anything wrong with it?