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Thread: Hi, just bought one '90 735i , has issues

  1. #1
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    Hi, just bought one '90 735i , has issues

    Hello all,
    I'm Dave, I just scored a clean '90 735i for my mom, $1200, but 345,000 miles. She loves it, but the factory tape player didn't work, it doesn't want to cold-start, then it won't idle until warm, wants to die at stops when you try to get going again, and begins to shimmy around 45 MPH. Seller says it needs new tie rod ends, I got those ordered. Seems to have some clatter under the valve cover?
    No problem removing the old tape player, wiring in a new Pioneer DEH-X6810BT is proving harder than any other. I grabbed a cheap universal 6x9" 3-way from one of my old Camaros, I can get sound out of it, but I try the exact same wiring to the BMW speaker wires, nothing. Any help, please?

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    Get it to an indy and see what it needs. The engine is basically unkillable, but it's time for some love. Do a quick valve adjustment, and put in some heavy oil (e.g Rotella T6 15w40) for this change.

    I'd say fluid change from the trans to the coolant to the brakes. If the trans is still original, it'll need new fluid badly. As for the speaker and the stalling, no idea. Also get the control arm bushings, they're only good for 30k.

    Pics?
    Last edited by XAlt; 07-26-2016 at 04:06 PM.

  3. #3
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    The previous owner bought the car new, always had it serviced at the dealership, BMW of Murray, UT, they have full records, I just don't have them yet.
    I'll check out the control arm bushings, if I do them I'd prefer polygraphite, if available.
    I got the audio figured out, I wired the new CD RDS receiver up and am mounting it in the glovebox, it has a remote, I spliced in a new Pioneer head unit with a tape player, the last one still on the market, because my mom has a lot of classical music tapes. But I'm looking at smartphone mounts, her 16-gig phone can hold 2250 songs, the CD player is smartphone compatible, and I'm getting it an I-Pod Shuffle, again for the CD changer.
    She's 70, but still sharp, and likes road trips.
    I drove the car, and was unimpressed. half the horses are missing, and it has an axle ratio closer to 3:1 when it needs something closer to 4:1, and what's with the 1600-stall torque converter? It needs something more like a 2200-RPM stall.
    The transmission fluid is cherry red, not burnt, so it's good.
    I have a half gallon of ZDDP additive, so I'll add a little of that when I adjust the valves. What's the best lash spec for helping lower-RPM torque?

    - - - Updated - - -

    Ok, ordered 2 lower control arm bushings, 2 upper control arm bushings, L & R tie rod ends, all 3 belts, a pair of front trailing arm bushings, and an idler arm bushing. All that plus an alignment should end the shimmy.

  4. #4
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    What I'm really confused about is the idle hunting.


    Pretty sure yours is 3.91. I mean, the only thing you can go for is a 4.27 that was found in the 1991+ 735s.
    Last edited by XAlt; 07-26-2016 at 07:03 PM.

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    Check and replace the distributor and rotor, IMO they are incredibly overlooked by owners who dont really know these cars. You also have the ICV you need to check.
    The 45mph shimmy is a common problem and you are looking at more than just tie rod ends. I had to end up replacing all front end components before I got rid of the shimmy. Try putting the front end on ramps and get underneath and start grabbing suspension parts and shaking them to find any play.

    This comes from the member Shogun on this forum:

    A major problem with the Bmw E34 especially the M30 3.5l out of the 535i: erratic idle. Don't expect your M30 to idle like a new car, but here is some tips to improve it:
    Check list from the less expensive to the more. Start by pouring some injector cleaner in at least two tanks of fuel.

    Air intake leak:
    A leak in the intake or vacuum leaks (check the dipsick o-ring seal and oil filter seal) will make your car idle roughly.

    Valve setting:
    If you didn't adjust your valve lately, check your valve adjustments.

    Spark plugs:
    Old spark plugs will make your car idle and run rough. Change them, good time to try those expensive Bosch platinum +4. Some owner use a slightly greater clearance: set them slightly larger to 0.86-0.91mm (0.034-0.036in) to help improve the idle with the stock plugs.

    Distributor cap and rotor:
    After a lot of miles (or km) your rotor and cap will be sad looking or cracked, check for yourself.

    Ignition wires:
    Check the ignition wire resistance with a multi-meter, it should be around 0 Ohm.

    Idle Control Valve (ICV):
    This expensive part gets dirty. You should clean it (along with the throttle body) each time you adjust your valves with carburator cleaner. If there is no improvement and your ICV had never been changed (there is sometimes a year stamped onto the casting), change it.

    Other considerations are: leaking injector, faulty temperature sensor, faulty oxygen sensor, check all electrical connections.

    http://www.bmwe34.net/E34main/Trouble/Hunting_idle.htm

    http://forums.bimmerforums.com/forum...M30-won-t-idle!

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  6. #6
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    Quote Originally Posted by 734i View Post
    I drove the car, and was unimpressed. half the horses are missing, and it has an axle ratio closer to 3:1 when it needs something closer to 4:1, and what's with the 1600-stall torque converter? It needs something more like a 2200-RPM stall.
    The transmission fluid is cherry red, not burnt, so it's good.
    I have a half gallon of ZDDP additive, so I'll add a little of that when I adjust the valves. What's the best lash spec for helping lower-RPM torque?.
    Congrats on your ride. I just bought the same car off of an original owner with 182k on it about 9 months ago or so. I must admit once I tuned mine and got it right. Mine will pull hard and has plenty of power and torque. Not sure what my diff ratio gears are. But I found out quickly its posi. I pulled out in front of somebody by accident, and floored it and turned the car sideways.

    I dont pound mine hard normally. I want to change my plastic timing chain guide rails, they look old.
    Last edited by TonyPa; 07-27-2016 at 02:07 AM.

  7. #7
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    Huge thanks to all of you for all the info!
    When she took it for a test drive, she spun both rear tires in the dirt, but I attributed that to the dirt, because a 3.43L doesn't need a limited-slip differential. I'll hafta check that before winter, and give it new gear lube while I'm in there.
    If it's already that closr to the most gear possible, then no sense changing it for such a small improvement, but how tall must first gear be? When cars are geared well, first gear should redline at 35 MPH, maybe 40 for a big-block V8 or a turbocharged V8.
    If the rest of the car outlasts either the engine or the transmission, I'll swap in a GM LSx V8 with a 4L60E, it has a decent 3.059:1 first gear.

  8. #8
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    Quote Originally Posted by 734i View Post
    Huge thanks to all of you for all the info!
    When she took it for a test drive, she spun both rear tires in the dirt, but I attributed that to the dirt, because a 3.43L doesn't need a limited-slip differential. I'll hafta check that before winter, and give it new gear lube while I'm in there.
    If it's already that closr to the most gear possible, then no sense changing it for such a small improvement, but how tall must first gear be? When cars are geared well, first gear should redline at 35 MPH, maybe 40 for a big-block V8 or a turbocharged V8.
    If the rest of the car outlasts either the engine or the transmission, I'll swap in a GM LSx V8 with a 4L60E, it has a decent 3.059:1 first gear.
    You make that sound so easy, I love your enthusiasm.

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    Quote Originally Posted by htrdbmr View Post
    You make that sound so easy, I love your enthusiasm.
    maybe he has seen your engine bay ;-) http://www.bimmerboard.com/members/h...GIE%20TIME.jpg
    Shogun tricks and tips for the E32 series are HERE!

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    Quote Originally Posted by 734i View Post
    Huge thanks to all of you for all the info!
    When she took it for a test drive, she spun both rear tires in the dirt, but I attributed that to the dirt, because a 3.43L doesn't need a limited-slip differential. I'll hafta check that before winter, and give it new gear lube while I'm in there.
    If it's already that closr to the most gear possible, then no sense changing it for such a small improvement, but how tall must first gear be? When cars are geared well, first gear should redline at 35 MPH, maybe 40 for a big-block V8 or a turbocharged V8.
    If the rest of the car outlasts either the engine or the transmission, I'll swap in a GM LSx V8 with a 4L60E, it has a decent 3.059:1 first gear.
    4L60E, hehehehe. slushslushslush. Well, basically any properly working big six of the era, whether it be an E24, 28, 32, 34 tends to hit redline at 40 mph (at least the manual E34s and some beat up E24 L6 I've tried out).

    It'd be cool to see what that 345K E32 looks like though, and how the body held up over the years? I've yet to see one rusted out here in the salt belt.
    Last edited by XAlt; 07-27-2016 at 11:57 AM.

  11. #11
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    Quote Originally Posted by XAlt View Post
    4L60E, hehehehe. slushslushslush. Well, basically any properly working big six of the era, whether it be an E24, 28, 32, 34 tends to hit redline at 40 mph (at least the manual E34s and some beat up E24 L6 I've tried out).

    It'd be cool to see what that 345K E32 looks like though, and how the body held up over the years? I've yet to see one rusted out here in the salt belt.

    Yes I agree. I would like to see some photos with that mileage on a too. Im hoping mine looks good when it hits that high of a mileage, and hopefully last that long. Mine is a 1990, and it has no rust on it and no Bondo and I am in the salt belt also. Although I do have fading on top of mine. Salt is definitely not our friend, but somehow these cars held up extremely well.

    - - - Updated - - -

    Quote Originally Posted by 734i View Post
    Huge thanks to all of you for all the info!
    When she took it for a test drive, she spun both rear tires in the dirt, but I attributed that to the dirt, because a 3.43L doesn't need a limited-slip differential. I'll hafta check that before winter, and give it new gear lube while I'm in there.
    If it's already that closr to the most gear possible, then no sense changing it for such a small improvement, but how tall must first gear be? When cars are geared well, first gear should redline at 35 MPH, maybe 40 for a big-block V8 or a turbocharged V8.
    If the rest of the car outlasts either the engine or the transmission, I'll swap in a GM LSx V8 with a 4L60E, it has a decent 3.059:1 first gear.

    If you do have a posi rear end, I use Redline synthetic. Shogun recommended it to me, and that's exactly what I used. I got mine from Summit pretty reasonable. I think mine was 75 w/140 without going in the garage and looking.

    But that is for a posi rear end only.
    Last edited by TonyPa; 07-27-2016 at 01:17 PM.

  12. #12
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    Quote Originally Posted by htrdbmr View Post
    You make that sound so easy, I love your enthusiasm.
    Thanks! Which part? Changing gear lube is an hour's work, or less, on a Saturday morning. About a half hour to find the approximate axle ratio.
    I've done a few different LSx swaps; Fiero, 300ZX, S-10, and Camaro.

    - - - Updated - - -

    Quote Originally Posted by shogun View Post
    maybe he has seen your engine bay ;-) http://www.bimmerboard.com/members/h...GIE%20TIME.jpg
    Sweet! If I had an LT1, as my '95 Z28 had, I'd put it in my S-10.

    - - - Updated - - -

    Pics tomorrow

  13. #13
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    got pics, the reply box has no options to attach. I'm not uploading them to photobucket to link them that way, too much of a pita

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    Insert image. third to the last on the right

    imgur>photobucket

    Do it for the family.
    Last edited by XAlt; 07-28-2016 at 02:17 PM.

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    Do it for the family.
    +1

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  16. #16
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    Quote Originally Posted by SergeBMW View Post
    +1
    +2

  17. #17
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    I replaced the belts and thermostat again, that didn't solve anything. I replaced the belt-driven fan with an electric fan, that improved nothing. Lastly will be no thermostat. I'm hoping that either ends the overheating or destroys the shizzy inline 6 to make way for the GM LS3 V8 swap. Since I last posted, I've seen one of these 735i cylinder heads disassembled, the ports are not configured for flow, especially not with turbocharging. So I hope no t-stat kills it, the ZF auto trans ratios are shizzy also, about the same as the Ford A4LD and the GM 4L80E, both of which I also have, and both of which I also hate. Gimme a 4L60E anyday, like my wife's '03 Astro has.

    - - - Updated - - -

  18. #18
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    Quote Originally Posted by 734i View Post
    I replaced the belts and thermostat again, that didn't solve anything. I replaced the belt-driven fan with an electric fan, that improved nothing. Lastly will be no thermostat. I'm hoping that either ends the overheating or destroys the shizzy inline 6 to make way for the GM LS3 V8 swap. Since I last posted, I've seen one of these 735i cylinder heads disassembled, the ports are not configured for flow, especially not with turbocharging. So I hope no t-stat kills it, the ZF auto trans ratios are shizzy also, about the same as the Ford A4LD and the GM 4L80E, both of which I also have, and both of which I also hate. Gimme a 4L60E anyday, like my wife's '03 Astro has.

    - - - Updated - - -
    If you want to kill the car fast, neutral drops are the best option, 4HP22 clutch packs are made of melted cheese and even the 4HP24 realistically isn't going to withstand more than 500hp, the manuals on the other hand.... Some builds use the M106 "745i" engine with larger valves to force air into the heads. Wiling to bet your symptoms are a vacuum leak, ICV or fuel supply. They don't take too kindly to overheating either, number one cause of death is the HG.

    http://www.firstfives.org/faq/cylind...r_head_faq.htm

    With your expertise the LS is an obvious choice, there's a reason the 6 was phased out for a torquey V8 towards the end of production.
    Last edited by XAlt; 05-25-2017 at 08:22 PM.

  19. #19
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    Except for the overheating, it drives relatively well. Power is relatively good, driveability is good. No loss of coolant until the gauge gets above 3/4, no strange noises. It's a very nice drive, unless you want to get across an intersection quicker than any other 6 cylinder car, from a dead stop.
    I'm still not sure if this thing has a 188 or 210 mm rear, I found a 3.15:1 188 gearset at a good price on Ebay, I think I could sell this 3.91:1 for the same amount.

  20. #20
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    Quote Originally Posted by 734i View Post
    Except for the overheating, it drives relatively well. Power is relatively good, driveability is good. No loss of coolant until the gauge gets above 3/4, no strange noises. It's a very nice drive, unless you want to get across an intersection quicker than any other 6 cylinder car, from a dead stop.
    I'm still not sure if this thing has a 188 or 210 mm rear, I found a 3.15:1 188 gearset at a good price on Ebay, I think I could sell this 3.91:1 for the same amount.
    HG probably went, might as well nuke it with a mechanic in a can and see how long it lasts, they're also a pain to bleed but that doesn't explain water consumption. 188mm internals do swap over but you'll need to keep your medium case. 735s had a 188 like most E34s, only the 540\740\750\M5 used the big case.

    The entire engine lineup until 1990 was more or less based on the 4-cyl M10 block and scaled up as needed. New multivalve heads made the real difference when it came to the power wall. F1 builds ran at 80-90psi (for a few laps) on stock blocks that were apparently pissed on and left outside, but nobody really knows what happened.

    http://raceenginedesign.biz/BmwM12.htm
    https://www.bmw2002faq.com/forums/to...for-m10-block/
    http://www.unixnerd.demon.co.uk/s38.html
    Last edited by XAlt; 05-25-2017 at 08:24 PM.

  21. #21
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    Xalt, I want to thank you for all your replies, the dialog is much appreciated.
    I am UAW trained as an automotive engine machinist, I passed the ASE pre-certs, and I have several years of real-world experience in engine rebuilding, machining, and performance building. As such, it seems to me that the HG is ok, because if it failed, then it would be losing combustion pressure, which would be venting to one of 4 possible places. (1) engine bay, which would be easily audible. (2) Coolant passage, which would cause coolant loss even at cold-start idle. (3) oil passage, which would at least escape past the dipstick, easily audible. (4) Another cylinder. Power would be down enough to notice, but it runs as strong as the day we brought it home.
    The BMW online community is very different from Camaros or Mustangs, and I'm finding it easier to deal with, but solid facts are far fewer, and far more difficult to accumulate.
    I always planned to crawl under and measure, to determine which diff it has. I've been assuming 188, and in all honesty, the 188 is probably strong enough for a turbo LS3 / 4L75E, which is what I hope to end up with. Because this car will never see any tire stickier than a 275/40R17 with a treadwear number of 200 or more. Leaning toward a BFG g-Force COMP-2 A/S, on 9.5s rear. Up front I'm thinking 17x8s with 235/45s.
    That 3.15 gear would put the cruise RPM right where I want it, so I'll place a bid on it. I found several 2.93s, that's a bit less than ideal.

  22. #22
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    There's a couple LQ4 guys on the E34 forum that could be of use, a post there could be handy. Is turbo lag usually negated by the automatic transmission in these big power V8 builds!


    By the way, the full site will let you upload pics from your phone, vBulletin at its finest...
    Last edited by XAlt; 05-26-2017 at 01:09 PM.

  23. #23
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    If there's any noticeable turbo lag then the turbo(s) hot side a/r is excessive. Even copying STS remote mounting ( in place of muffler, after-cat(s) making it emissions-legal ) doesn't have enough lag to worry about. I used to have my shop 100 feet from his ( Squires of STS ) so I'm familiar with his results.

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