ZHoob2004
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Posts posted by ZHoob2004
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Make sure the afm is installed and securely connected, and make sure the boot isn't torn. You can test the afm fuel cut by turning the key to on and moving the flap with your hand. The fuel pump will turn on.
I personally had a similar problem with my motor that I found to be the injectors falling to fire after initial startup, causing it to run off the cold start alone, so also make sure your ignition is properly connected to your injection system.
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Maybe not directly relevant, but on my 77 a previous owner had decided it was a good idea to jumper the front markers to the headlights.
I'd take the bulbs out and check resistance to ground, and if they have any continuity to each other. That should help you track it down.
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I doubt it's easy/possible to do in New York, but I think a modern 432 clone with a carbed rb20 would be pretty slick. Probably not emissions legal anywhere, actually.
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The Mr. Gasket fuel pressure gauge kit off amazon worked well for me on my triple weber conversion. My fuel in line runs from my filter to the firewall, along the firewall to the drivers side then to the rearmost carburetor first and I mounted the gauge with a little home made bracket that bolts up to where the throttle linkage bolts to the firewall.
Keep in mind that efi and carb systems operate in completely different pressure ranges, so a carb gauge won't work for efi and vise versa
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Not at the moment, but it's fairly straightforward. I got a 1/8 npt gauge off amazon, a matching tee fitting from a local hardware store and I already had the 5/16-1/8 npt hose barbs. Add some thread sealant and a couple clamps and there you are.
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I just put one between the filter and the fuel rail, seems accurate enough to tell me the regulator is working and nothing's clogged.
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TPS problem? It could be failing to switch to the wide throttle fueling due to corroded contacts either inside the tps or its connector. Check all your harness connections and make sure they're clean and check the tps contacts and make sure it's properly set. Could also be a problem with ignition not advancing with engine rpm, but I don't know how to troubleshoot that.
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Well everyone, I've found the magic. Since the cams didn't turn out to be the problem, I moved onto the next step, the AFR. I got my exhaust welded the other day and I finished installing the wideband today and now I feel like an idiot. Motor was SUPER lean (>20:1 AFR) all over the place, no wonder it drove like garbage. I decided to take a look at the questionable wiring on the injectors and as soon as I touched one I heard the engine sound change and saw the AFR improve. Based on that, I cleaned and reseated the injector wiring and I'm now running a nice ~14.5 at idle with good AFR and power all around.
After fixing the fueling problem, the motor is butter smooth and the power is right where I imagined it would be. I feel kind of stupid for not noticing that the motor was running so poorly but I'm going to attribute it to being used to 4 cylinders and not realizing how smooth the l6 can be. Thanks again for all the suggestions, everyone.
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It's taken about twice as long as I said it would but I'm back wrenching on the car today. I just looked at the cam in the motor and it's internally oiled and stamped "A", which should put it as a later n47 cam, same specs as my other one and not the maxima cam. I'm going to verify the cam timing right now and get my wideband install finished.
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A p79 head might help. The valves are bigger and with flat tops compression would be pump gas friendly. I had an 83 5 speed f54 flat top /p79 with megasquirt it was not the fastest car but very fun to drive.
Unfortunately, this would require me to source either pistons or a 3rd complete block, neither of which I am fond of doing at this moment.
What Tony was saying is true, on top of that the stock EFI is probably limiting you.
Here is my dyno of an stock L28 (f54/p79 combo) with SU's and a 6-2-1 msa header
You can see it falls off.
One other thing I can think of is the weight difference. I know the CRX's weigh like 2300lbs tops fully loaded. Your Z is a little heavier than that. My engine is in a 2100 lbs 240z.
That makes sense, and I'm grateful for the information.
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A B16 in a CRX is a hot little combo. Having a little experience with Hondas 15 years ago, I'd say your car with the stock motor is probably similar to a CRX Si in stock form.
First step is getting the wideband on there to see how yours is even running. With a stock cam, and the smaller valves (and high compression) you should have a torquey little motor, but it won't have the same feeling as your CRX. They pulled pretty hard past 4k. Do you have a stock manifold? I have no experience but I've heard the 6-1 header can seriously rob low end grunt. Your head probably won't flow enough in it's current form to take advantage of it's benifits.
Work with what you have and try to get it all to work together.
An L28 is dead at 5300 which is why they were geared for that at top speed.
If you want more power on the top end, you will need a real cam, and not something from another L-Series.
Even the early heads from the L24 are not going to make that much of a measurable difference in performance gain.
Thanks both of you, this is exactly the sort of advice I was hoping to hear. Some searching told me I shouldn't have any immediate problems with switching the cams (and caps for oiling) between the heads on the car, so that and wideband are immediately happening, then it's to the drawing board for how I'm going to set up my fueling. As for the header, I do have the stock header (both z and zx), so that may be an option as well. Luckily, the used exhaust I picked up should be able to bolt on to the stock system just as well as it does the long header.
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Overall, my impression is that it's low on power everywhere, more so up high. All filters and fluids are brand new, I can't rule out the rich efi (though it's definitely better than it used to be)
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Plugs were alright last I checked, but that was a while ago. I'll try to get the exhaust welded this week and move the wideband over on Saturday and see where I'm at there.
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So then, based on the advice received in this thread so far and a bit of research on my own, my action plan is as follows:
Right now -
N47 cam in head (still need to figure out if this is feasible)
wideband - check AFM
Future -
real cam
standalone EMS
head work
close-ratio transmission?
Does this seem solid?
And to clarify, I don't expect this motor to rev anything like the honda, but I'm hoping to approach similar power output. The honda is high revving and makes little torque, the l28 I hope for medium revs and medium torque
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Another idea I just thought of was could I switch the cam from my other head to the maxima head? The maxima is internally oiled and the old head is using a spray bar
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Ok, that all makes sense and I admit that I don't know all of what I have. I did check and replace all gaskets in the motor and have the cam timed to the #1 position. Motor was reassembled according to the rebuild book. I have a wideband in my Honda that I plan to move over to check the fueling. Anything else I should be doing to get a handle on what I have and what it's doing? I still have the stock motor as well, but it needs a bore and valve job. Would pushing towards an aftermarket ems and cam be an advisable course? Could this all be the fault of my afm?
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What does it not do? Burnouts, wheel-stands, 140 mph...?
I'm hoping it can feel similar to my Honda but with more torque and less fear of speed bumps
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Alright, I can understand the gearing and the fuel being potential problems. So far I'm working with what I have and EMS and a cam are definitely in the future for this motor. Is there any reason I would be making less power than stock with this setup, and can I adjust something to compensate? Does the difference in valve size between the maxima and l28 make that big a difference? I also have a regular n47 around (needs seals), would that give me more power for the time being?
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I recently (read: 9 months ago) acquired a 77 280z which I have been fixing up. Within the past few weeks, it's finally been ready to drive up and down the street and it doesn't really seem to be anywhere close to what I was expecting.
So far with the car, I've swapped in a used L28 from a local acquaintance with an n42 block and mn47 head. Swapped the car from auto to 5 speed (I believe 280z) and the r180 in the back for an r200 (3.7 gears). Intake is a 280zx manifold and exhaust is an msa 6-1 header going out a straight-through muffler. Fuel system has been fully cleaned and repaired with the addition of a gauge just after the filter, using stock 280z efi. Ignition is a 280zx matchbox set to ~35 degrees total advance.
As for expectations, I know I'm not making a ton of power, but am I right to expect more than the stock 130? If so, is there something missing I should have done to take advantage of these mods?
This is my second car, and I was never able to drive it in stock form, so my only comparison is my B16 (160 claimed) swapped CRX with basic bolt-ons.
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Or....the wiring wasn't right.
Entirely possible. Main symptom that caused me to blame the ECU was that the rear 3 injectors were powered as long as battery power and the ecu were connected to the system. Other contributor to that was the associate I got the engine from said the engine last ran only on starting fluid and he didn't diagnose it, and that fits with what I experienced (essentially running on the cold start injector).
Of course, I was not able to test another ECU or harness, so either could be at fault along with my wiring, which was ~6 connections, I'm pretty sure all of which go to +12v (and the coil connection)
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I guess it's time I give an update. I found the easiest way to get it working was to grab a 280zx fusible link block and hook the harness up through that. I'd like to say that it started right up after that, but it turns out my 280zx ecu was bad and half the injectors were always on, half were always off. Swapped the stock 280z harness/ecu back on and it started right up.
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So I haven't had a chance to look close at the harness for about a week, but am I incorrect in thinking the main difference is the connection to the combination switch (or lack thereof) and the fusible link connections? Unfortunately I can't find any decent pictures of a complete zx harness to compare to.
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I'm swapping a 280zx (N/A) motor into my 280z, can I use the newer 280zx harness/ecu without too much trouble? My harness on the stock motor is a bit butchered from previous owners. Anyone know anything I need to watch out for?
Tuning safe to do on a coolant burning engine?
in MegaSquirt
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Imho any tune you can come up with for this combo will be no better than an estimated basemap for your new build. If you want to mess around with tuning and see what it likes go ahead, but I wouldn't expect to take any tune you come up with straight to your new motor.