1990 190e running issues

[kendogg]

Hello, I recently picked up a 1990 190e 2.6, and it has some issues. I purchased the car not running. I discovered that the car had the wrong spark plugs installed (Bosch HR9DC). These are resistor-type spark plugs, and this car requires non-resistor plugs. I have full service history, and the car has 118k miles. It explains why the car has had 2 new coils installed in the past 10k miles, and has been thru 3-4 caps & rotors in it's life. I found a set of Denso non-resistor plugs and installed them, and the car fired right up.

Now, I'm going to build a smoke tester to check for vacuum leaks this weekend. The car takes a few tries to fire up cold, but once it's running, I can shut it off and it fires right back up. From idle, it seems I have to give it significant throttle to get the car to do anything, but once it's moving and the revs are up, small % throttle input makes the car act as-normal. On a WOT run, it seems to shift to 2nd gear at roughly 5500 rpm's, and shifts to 3rd about 6500 rpm's. Haven't had enough road yet to go any higher I've adjusted the idle screw a bit (somebody tinkered with it before me, and it idled and started like crap, so it's running fairly smoothly. I plan to replace the O2 sensor shortly, mainly because on the previous 3-4 receipts the shop had recommended it, and it was declined by the PO. I've read I can use the generic 4-wire Mustang 5.0 O2 sensor on this car, right??

If I wanted to do some fuel system maintenance, what should I look at? I've considered picking up one of those inexpensive ultrasonic cleaners and tossing the injectors in it. Good idea? What solution should I use in one to clean them, if so? Also, on my first test drive out of the neighborhood, it popped a heater hose (the one on the back of the head), probably the only not-new hose in the system. Where should the temp needle normally sit? The car had a line at 80, then a line halfway between 80 and hot. It seemed to hover around the line between the 2, and then the needed went up a bit, then came back down. As I was backing into my driveway, the hose burst. 90% of the cooling system has been replaced within 10k miles. Should I simply replace the burst hose, put a new OEM t-stat in it for a 'just incase' measure, and bleed it well?


I'm sure I'll ahve other questions soon, but this should do me for now. Anything else I should look into on the car? And I'll list the maintenance history below, so you all can see whats been done to help advise. Thanks in advance!!


1990 190e 2.6
118,xxx miles

116,445 - crank sensor
115,571 - coil, eha valve
110,017 - fan bearing bracket & pulley
109,806 - water pump, bypass hose, water line, thermostat, both radiator hoses, coolant level sensor, tie rods, idler arm, drag link, steering shock, ball joint, idler pulley & serpentine belt, belt shock, valve cover gasket, 2 breather hoses, front pads & rotors
109,051 - exhaust hanger, exhaust resonator
109,007 - coil, distributor cap & rotor, OV Relay, spark plugs
108,998 - rear pads & rotors, hood pad
105,860 - reman transmission installed, kickdown switch, rear main seal, front flex disk, trans cooler hoses,
83,422 - heater valve, rear muffler
(mileage unknown, 2 months previous to above W/O) - radiator, valve cover gasket, oil level sensor, front flex disk
75,507 - MAS control relay
75,425 - R134a conversion, full fluids change, spark plugs, air filter, p/s filter, serpentine belt, engine mounts, front shifter bushing
70,815 - distributor cap & rotor, spark plugs
70,322 - MAS control relay
66,715 - throttle cable, front pads & rotors
47,385 - serpentine belt, water pump, rear brake pads
47,113 - thermostat, thermostat housing, temp sensor
41,678 - front brake pads
27,612 - rear differential - warranty
15,746 - spark plugs, air filter,



And a handful of receipts from <15k miles, custom complains of coolant leaks, dealer techs could never find them, 'tighten hose clamp' type of receipts. It seems like this car has had a LOT of unnecessary maintenance, enough thats really making me wonder if I should even keep it. That, or idiotic technicians have just replaced everything under the sun whenever they could, especially when they didn't know how to actually diagnose a problem.....

[Stretch]

Ahhhggg! Information overload.

(I'll just answer one bit)

The best way of tackling the vacuum system is to buy / borrow a gauge and measure it. Your transmission will operate on vacuum and a Bowden cable linkage. I'd have a look at the condition of the throttle linkage and the connection to the Bowden cable first.

[kendogg]

Seriously? In 1990, the transmission is still run off vacuum and a bowden cable?? fml.....

[Edward Wyatt]

Ultrasonic cleaner won't help with CIS injectors, they really can't be cleaned off the car.

The hard starting might be fuel pressure related.

[kendogg]

Originally Posted by Edward Wyatt

Ultrasonic cleaner won't help with CIS injectors, they really can't be cleaned off the car.

The hard starting might be fuel pressure related.

Ya, getting to the junkyard at some point to collect some fittings off cars to build a fuel pressure tester for this car was definitely part of the plan. But if fuel pressure was low, wouldn't it run like **** at WOT under load?

[kendogg]

Bump, anybody? I've found how-to's on how to adjust the throttle plate, the EHA, and the idle mixture. I'm going to order a new Mustang 5.0 O2 sensor here shortly. And probably a bottle or 2 of Reline fuel system trreatment. And I'll still put together a fuel pressure tester to be able to monitor my fuel pressure for a bit and make sure everything is OK there as well.

[Stretch]

Go to www.startekinfo.com

Look on the the left hand side and follow the link to MB workshop resources then look for Service manual library CD/DVD

You'll find the W201 FSM there.

[just-n-time]

Originally Posted by kendogg

Bump, anybody? I've found how-to's on how to adjust the throttle plate, the EHA, and the idle mixture. I'm going to order a new Mustang 5.0 O2 sensor here shortly. And probably a bottle or 2 of Reline fuel system trreatment. And I'll still put together a fuel pressure tester to be able to monitor my fuel pressure for a bit and make sure everything is OK there as well.

You can clean them out of the engine, put a few drops in the top of your injector and use an air nozzle with rubber tip apply air to the top of injector and the injector will pop open and flush the system.I did mine this way and used wd40 works well. by the way used injector cleaner(Chevron) and then WD40 for lube after cleaning.

[kendogg]

Hi guys! OK, I installed the new O2 sensor. Replaced the popped heater hose, along with a new thermostat as a 'just in case' measure.

Got myself a new DMM that reads duty cycle. Engine cold, pins 2 & 3 on the X11. 70% duty cycle KOEO. Start car, immediately drops to 50% and stays there for a few minutes until it goes into closed loop, where it quickly rises to ~90%, and no matter what I do with the mixture screw on top, it stays there. Give it some throttle, and DC drops into the 50's, and then pops right back up to 90%. Footnote - cold start still sucks, has to crank and crank, seems like it's slowly, one at a time, firing off cylinders until it'll stay running on it's own without holding the key.


What gives guys? What do I need to look at?

[smp]

did you install that sensor correctly? I friend of mine had that same reading scenario until he replaced his O2 sensor.

Regarding injectors .. I replaced mine and it made all the difference. I had idle issues and rough running .. did everything else one would try and finally replacing the injectors sorted me out proper. With that much mileage you may as well go for it if you're planning on keeping the car. It's an easy job and not too expensive. Once you have new injectors in you can safely eliminate them as a variable. Cold starts could be cold start valve, try to get one at the JY.

Test your vacuum with a gauge .. don't bother looking for leaks, just check what vacuum you're pulling at the intake manifold. Anything over 15/16 is pretty good IIRC. I would look for running problems elsewhere if you have sufficient vacuum at the manifold.

Replace your fuel filter too.
Looks like the car has had a lot of maintenance, that's a good thing. You're lucky you have those records. Car sounds like a keeper.

[kendogg]

Originally Posted by smp

Car sounds like a keeper.

Ha. Funny you say that. At this point, I'm pretty positive I'm going to sell it immediately as soon as it's running correctly, lol. I'm much more comfortable working on my BMW's, and the parts aren't nearly as expensive. This car just seems overly complicated, and electrically fragile.


As far as the O2 - it's not possible to screw it up, lol. It's a 3-wire. 2 whites (heater circuit), 1 black (sensor output).

[kendogg]

Well, might as well update. I recently got a chance to replace the coolant temp sensor. That fixed the cold start issue completely. Now it's just dialing the fuel in I think, which I'm going to take it somewhere to do. I've tried doing with with the DMM on duty cycle and it's just not working. I've got it about as close as I can get the main fuel mixture screw eyeballing it by how it sounds and reacts, but I'm still going to take it toa shop I know of and let them fine tune it. A friend knows them real well and used to work there for a bit, and they specialize in oldr Mercs, so I trust them to not screw anything else up.

[kendogg]

Ran the car by the local old German guy who specializes in CIS (MVP German Auto in Tucker, GA). I told him take his time with it, no hurry. He drove it around and made adjustments to the fuel distributor. Thats it. Says it runs great, just needs to be driven since it's sat for so long. He said run a few bottles of techron thru it and put some miles on it and it'll be perfect. So, that has be relieved. For Sale thread coming shortly